- 20 Aug, 2008 3 commits
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Nick Piggin authored
XIP can call into get_xip_mem concurrently with the same file,offset with create=1. This usually maps down to get_block, which expects the page lock to prevent such a situation. This causes ext2 to explode for one reason or another. Serialise those calls for the moment. For common usages today, I suspect get_xip_mem rarely is called to create new blocks. In future as XIP technologies evolve we might need to look at which operations require scalability, and rework the locking to suit. Signed-off-by:
Nick Piggin <npiggin@suse.de> Cc: Jared Hulbert <jaredeh@gmail.com> Acked-by:
Carsten Otte <cotte@freenet.de> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Nick Piggin authored
XIP has a race between sparse pages being inserted into page tables, and sparse pages being zapped when its time to put a non-sparse page in. What can happen is that a process can be left with a dangling sparse page in a MAP_SHARED mapping, while the rest of the world sees the non-sparse version. Ie. data corruption. Guard these operations with a seqlock, making fault-in-sparse-pages the slowpath, and try-to-unmap-sparse-pages the fastpath. Signed-off-by:
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Nick Piggin authored
There is a race with dirty page accounting where a page may not properly be accounted for. clear_page_dirty_for_io() calls page_mkclean; then TestClearPageDirty. page_mkclean walks the rmaps for that page, and for each one it cleans and write protects the pte if it was dirty. It uses page_check_address to find the pte. That function has a shortcut to avoid the ptl if the pte is not present. Unfortunately, the pte can be switched to not-present then back to present by other code while holding the page table lock -- this should not be a signal for page_mkclean to ignore that pte, because it may be dirty. For example, powerpc64's set_pte_at will clear a previously present pte before setting it to the desired value. There may also be other code in core mm or in arch which do similar things. The consequence of the bug is loss of data integrity due to msync, and loss of dirty page accounting accuracy. XIP's __xip_unmap could easily also be unreliable (depending on the exact XIP locking scheme), which can lead to data corruption. Fix this by having an option to always take ptl to check the pte in page_check_address. It's possible to retain this optimization for page_referenced and try_to_unmap. Signed-off-by:
Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by:
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- 28 Jul, 2008 1 commit
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Andrea Arcangeli authored
With KVM/GFP/XPMEM there isn't just the primary CPU MMU pointing to pages. There are secondary MMUs (with secondary sptes and secondary tlbs) too. sptes in the kvm case are shadow pagetables, but when I say spte in mmu-notifier context, I mean "secondary pte". In GRU case there's no actual secondary pte and there's only a secondary tlb because the GRU secondary MMU has no knowledge about sptes and every secondary tlb miss event in the MMU always generates a page fault that has to be resolved by the CPU (this is not the case of KVM where the a secondary tlb miss will walk sptes in hardware and it will refill the secondary tlb transparently to software if the corresponding spte is present). The same way zap_page_range has to invalidate the pte before freeing the page, the spte (and secondary tlb) must also be invalidated before any page is freed and reused. Currently we take a page_count pin on every page mapped by sptes, but that means the pages can't be swapped whenever they're map...
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- 26 Jul, 2008 1 commit
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Miklos Szeredi authored
All calls to remove_suid() are made with a file pointer, because (similarly to file_update_time) it is called when the file is written. Clean up callers by passing in a file instead of a dentry. Signed-off-by:Miklos Szeredi <mszeredi@suse.cz>
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- 28 Apr, 2008 1 commit
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Nick Piggin authored
Convert XIP to support non-struct page backed memory, using VM_MIXEDMAP for the user mappings. This requires the get_xip_page API to be changed to an address based one. Improve the API layering a little bit too, while we're here. This is required in order to support XIP filesystems on memory that isn't backed with struct page (but memory with struct page is still supported too). Signed-off-by:
Carsten Otte <cotte@de.ibm.com> Cc: Jared Hulbert <jaredeh@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by:
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- 08 Feb, 2008 1 commit
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Jan Kara authored
Convert variables containing page indexes to pgoff_t. Signed-off-by:
Jan Kara <jack@suse.cz> Signed-off-by:
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- 05 Feb, 2008 1 commit
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Christoph Lameter authored
Simplify page cache zeroing of segments of pages through 3 functions zero_user_segments(page, start1, end1, start2, end2) Zeros two segments of the page. It takes the position where to start and end the zeroing which avoids length calculations and makes code clearer. zero_user_segment(page, start, end) Same for a single segment. zero_user(page, start, length) Length variant for the case where we know the length. We remove the zero_user_page macro. Issues: 1. Its a macro. Inline functions are preferable. 2. The KM_USER0 macro is only defined for HIGHMEM. Having to treat this special case everywhere makes the code needlessly complex. The parameter for zeroing is always KM_USER0 except in one single case that we open code. Avoiding KM_USER0 makes a lot of code not having to be dealing with the special casing for HIGHMEM anymore. Dealing with kmap is only necessary for HIGHMEM configurations. In those configurations we use KM_USER0 like we do for a series of other functions defined in highmem.h. Since KM_USER0 is depends on HIGHMEM the existing zero_user_page function could not be a macro. zero_user_* functions introduced here can be be inline because that constant is not used when these functions are called. Also extract the flushing of the caches to be outside of the kmap. [akpm@linux-foundation.org: fix nfs and ntfs build] [akpm@linux-foundation.org: fix ntfs build some more] Signed-off-by:Christoph Lameter <clameter@sgi.com> Cc: Steven French <sfrench@us.ibm.com> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Cc: <linux-ext4@vger.kernel.org> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Anton Altaparmakov <aia21@cantab.net> Cc: Mark Fasheh <mark.fasheh@oracle.com> Cc: David Chinner <dgc@sgi.com> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Cc: Steven French <sfrench@us.ibm.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by:
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- 08 Jan, 2008 1 commit
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Akinobu Mita authored
The use of get_zeroed_page() with __GFP_HIGHMEM is invalid. Use alloc_page() with __GFP_ZERO instead of invalid get_zeroed_page(). (This patch is only compile tested) Cc: Carsten Otte <cotte@de.ibm.com> Signed-off-by:
Akinobu Mita <akinobu.mita@gmail.com> Acked-by:
Hugh Dickins <hugh@veritas.com> Acked-by:
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- 05 Dec, 2007 1 commit
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Nick Piggin authored
Writing to XIP files at a non-page-aligned offset results in data corruption because the writes were always sent to the start of the page. Signed-off-by:
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- 16 Oct, 2007 1 commit
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Nick Piggin authored
Hide some of the open-coded nr_segs tests into the iovec helpers. This is all to simplify generic_file_buffered_write, because that gets more complex in the next patch. Signed-off-by:
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- 19 Jul, 2007 3 commits
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Nick Piggin authored
This patch completes Linus's wish that the fault return codes be made into bit flags, which I agree makes everything nicer. This requires requires all handle_mm_fault callers to be modified (possibly the modifications should go further and do things like fault accounting in handle_mm_fault -- however that would be for another patch). [akpm@linux-foundation.org: fix alpha build] [akpm@linux-foundation.org: fix s390 build] [akpm@linux-foundation.org: fix sparc build] [akpm@linux-foundation.org: fix sparc64 build] [akpm@linux-foundation.org: fix ia64 build] Signed-off-by: -
Nick Piggin authored
Change ->fault prototype. We now return an int, which contains VM_FAULT_xxx code in the low byte, and FAULT_RET_xxx code in the next byte. FAULT_RET_ code tells the VM whether a page was found, whether it has been locked, and potentially other things. This is not quite the way he wanted it yet, but that's changed in the next patch (which requires changes to arch code). This means we no longer set VM_CAN_INVALIDATE in the vma in order to say that a page is locked which requires filemap_nopage to go away (because we can no longer remain backward compatible without that flag), but we were going to do that anyway. struct fault_data is renamed to struct vm_fault as Linus asked. address is now a void __user * that we should firmly encourage drivers not to use without really good reason. The page is now returned via a page pointer in the vm_fault struct. Signed-off-by:
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Nick Piggin authored
Nonlinear mappings are (AFAIKS) simply a virtual memory concept that encodes the virtual address -> file offset differently from linear mappings. ->populate is a layering violation because the filesystem/pagecache code should need to know anything about the virtual memory mapping. The hitch here is that the ->nopage handler didn't pass down enough information (ie. pgoff). But it is more logical to pass pgoff rather than have the ->nopage function calculate it itself anyway (because that's a similar layering violation). Having the populate handler install the pte itself is likewise a nasty thing to be doing. This patch introduces a new fault handler that replaces ->nopage and ->populate and (later) ->nopfn. Most of the old mechanism is still in place so there is a lot of duplication and nice cleanups that can be removed if everyone switches over. The rationale for doing this in the first place is that nonlinear mappings are subject to the pagefault vs invalidate/truncate race too, and it seemed stupid to duplicate the synchronisation logic rather than just consolidate the two. After this patch, MAP_NONBLOCK no longer sets up ptes for pages present in pagecache. Seems like a fringe functionality anyway. NOPAGE_REFAULT is removed. This should be implemented with ->fault, and no users have hit mainline yet. [akpm@linux-foundation.org: cleanup] [randy.dunlap@oracle.com: doc. fixes for readahead] [akpm@linux-foundation.org: build fix] Signed-off-by:
Randy Dunlap <randy.dunlap@oracle.com> Cc: Mark Fasheh <mark.fasheh@oracle.com> Signed-off-by:
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- 10 Jul, 2007 1 commit
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Carsten Otte authored
This patch removes xip_file_sendfile, the sendfile implementation for xip without replacement. Those customers that use xip on s390 are not using sendfile() as far as we know, and so far s390 is the only platform this could potentially be used on so far. Having sendfile is not a popular feature for execute in place file systems, however we have a working implementation of splice_read() based on fs/splice.c if anyone asks for it. At this point in time, it does not seem preferable to merge splice_read() for xip because it causes extra maintenence effort due to code duplication and it requires struct page behind the xip memory segment. We'd like to get rid of that in favor of supporting flash based embedded platforms (Monta Vista work) soon. Signed-off-by:
Jens Axboe <jens.axboe@oracle.com>
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- 21 May, 2007 1 commit
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Alexey Dobriyan authored
First thing mm.h does is including sched.h solely for can_do_mlock() inline function which has "current" dereference inside. By dealing with can_do_mlock() mm.h can be detached from sched.h which is good. See below, why. This patch a) removes unconditional inclusion of sched.h from mm.h b) makes can_do_mlock() normal function in mm/mlock.c c) exports can_do_mlock() to not break compilation d) adds sched.h inclusions back to files that were getting it indirectly. e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were getting them indirectly Net result is: a) mm.h users would get less code to open, read, preprocess, parse, ... if they don't need sched.h b) sched.h stops being dependency for significant number of files: on x86_64 allmodconfig touching sched.h results in recompile of 4083 files, after patch it's only 3744 (-8.3%). Cross-compile tested on all arm defconfigs, all mips defconfigs, all powerpc defconfigs, alpha alpha-up arm i386 i386-up i386-defconfig i386-allnoconfig ia64 ia64-up m68k mips parisc parisc-up powerpc powerpc-up s390 s390-up sparc sparc-up sparc64 sparc64-up um-x86_64 x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig as well as my two usual configs. Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by:
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- 09 May, 2007 1 commit
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Nate Diller authored
It's very common for file systems to need to zero part or all of a page, the simplist way is just to use kmap_atomic() and memset(). There's actually a library function in include/linux/highmem.h that does exactly that, but it's confusingly named memclear_highpage_flush(), which is descriptive of *how* it does the work rather than what the *purpose* is. So this patchset renames the function to zero_user_page(), and calls it from the various places that currently open code it. This first patch introduces the new function call, and converts all the core kernel callsites, both the open-coded ones and the old memclear_highpage_flush() ones. Following this patch is a series of conversions for each file system individually, per AKPM, and finally a patch deprecating the old call. The diffstat below shows the entire patchset. [akpm@linux-foundation.org: fix a few things] Signed-off-by:
Nate Diller <nate.diller@gmail.com> Signed-off-by:
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- 29 Mar, 2007 1 commit
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Carsten Otte authored
Fix the bug, that reading into xip mapping from /dev/zero fills the user page table with ZERO_PAGE() entries. Later on, xip cannot tell which pages have been ZERO_PAGE() filled by access to a sparse mapping, and which ones origin from /dev/zero. It will unmap ZERO_PAGE from all mappings when filling the sparse hole with data. xip does now use its own zeroed page for its sparse mappings. Please apply. Signed-off-by:
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- 30 Jan, 2007 1 commit
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Hugh Dickins authored
Nick Piggin points out that page accounting on MIPS multiple ZERO_PAGEs is not maintained by its move_pte, and could lead to freeing a ZERO_PAGE. Instead of complicating that move_pte, just forget the minor optimization when mremapping, and change the one thing which needed it for correctness - filemap_xip use ZERO_PAGE(0) throughout instead of according to address. [ "There is no block device driver one could use for XIP on mips platforms" - Carsten Otte ] Signed-off-by:
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- 22 Dec, 2006 1 commit
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Nick Piggin authored
Add more debugging in the rmap code in an attempt to locate to source of the occasional "mapcount went negative" assertions. Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by:
Andrew Morton <akpm@osdl.org> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
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- 08 Dec, 2006 1 commit
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Josef "Jeff" Sipek authored
Change all the uses of f_{dentry,vfsmnt} to f_path.{dentry,mnt} in linux/mm/. Signed-off-by:Josef "Jeff" Sipek <jsipek@cs.sunysb.edu> Signed-off-by:
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- 28 Jun, 2006 1 commit
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Christoph Hellwig authored
Same as with already do with the file operations: keep them in .rodata and prevents people from doing runtime patching. Signed-off-by:
Christoph Hellwig <hch@lst.de> Cc: Steven French <sfrench@us.ibm.com> Signed-off-by:
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- 10 Jan, 2006 1 commit
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Christoph Hellwig authored
To allow various options to work per-mount instead of per-sb we need a struct vfsmount when updating ctime and mtime. This preparation patch replaces the inode_update_time routine with a file_update_atime routine so we can easily get at the vfsmount. (and the file makes more sense in this context anyway). Also get rid of the unused second argument - we always want to update the ctime when calling this routine. Signed-off-by:
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- 09 Jan, 2006 1 commit
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Jes Sorensen authored
This patch converts the inode semaphore to a mutex. I have tested it on XFS and compiled as much as one can consider on an ia64. Anyway your luck with it might be different. Modified-by:
Ingo Molnar <mingo@elte.hu> (finished the conversion) Signed-off-by:
Jes Sorensen <jes@sgi.com> Signed-off-by:
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- 30 Oct, 2005 3 commits
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Hugh Dickins authored
rmap's page_check_address descend without page_table_lock. First just pte_offset_map in case there's no pte present worth locking for, then take page_table_lock for the full check, and pass ptl back to caller in the same style as pte_offset_map_lock. __xip_unmap, page_referenced_one and try_to_unmap_one use pte_unmap_unlock. try_to_unmap_cluster also. page_check_address reformatted to avoid progressive indentation. No use is made of its one error code, return NULL when it fails. Signed-off-by:
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Hugh Dickins authored
Small fix to the PageReserved patch: the mips ZERO_PAGE(address) depends on address, so __xip_unmap is wrong to initialize page with that before address is initialized; and in fact must re-evaluate it each iteration. Signed-off-by:
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Nick Piggin authored
Remove PageReserved() calls from core code by tightening VM_RESERVED handling in mm/ to cover PageReserved functionality. PageReserved special casing is removed from get_page and put_page. All setting and clearing of PageReserved is retained, and it is now flagged in the page_alloc checks to help ensure we don't introduce any refcount based freeing of Reserved pages. MAP_PRIVATE, PROT_WRITE of VM_RESERVED regions is tentatively being deprecated. We never completely handled it correctly anyway, and is be reintroduced in future if required (Hugh has a proof of concept). Once PageReserved() calls are removed from kernel/power/swsusp.c, and all arch/ and driver code, the Set and Clear calls, and the PG_reserved bit can be trivially removed. Last real user of PageReserved is swsusp, which uses PageReserved to determine whether a struct page points to valid memory or not. This still needs to be addressed (a generic page_is_ram() should work). A last caveat: the ZERO_PAGE is now refcounted and managed with rmap (and thus mapcounted and count towards shared rss). These writes to the struct page could cause excessive cacheline bouncing on big systems. There are a number of ways this could be addressed if it is an issue. Signed-off-by:
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- 15 Jul, 2005 1 commit
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Carsten Otte authored
This patch includes feedback from Andrew and Christoph. Thanks for taking time to review. Use of empty_zero_page was eliminated to fix compilation for architectures that don't have it. This patch removes setting pages up-to-date in ext2_get_xip_page and all bug checks to verify that the page is indeed up to date. Setting the page state on mapping to userland is bogus. None of the code patchs involved with these pages in mm cares about the page state. still on my ToDo list: identify a place outside second extended where __inode_direct_access should reside Signed-off-by:
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- 12 Jul, 2005 1 commit
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Geert Uytterhoeven authored
mm/filemap_xip.c: In function `__xip_unmap': mm/filemap_xip.c:194: request for member `pte' in something not a structure or union Apparently pte_pfn() takes a pte_t, not a pointer to a pte_t. From looking at asm/page.h, it seems to be the same on ia32 or ppc (iff STRICT_MM_TYPECHECKS is enabled, which is disabled by default on ppc). Acked-by:
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- 24 Jun, 2005 2 commits
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Carsten Otte authored
This patch reworks filemap_xip.c with the goal to reduce code duplication from mm/filemap.c. It applies agains 2.6.12-rc6-mm1. Instead of implementing the aio functions, this one implements the synchronous read/write functions only. For readv and writev, the generic fallback is used. For aio, we rely on the application doing the fallback. Since our "synchronous" function does memcpy immediately anyway, there is no performance difference between using the fallbacks or implementing each operation. Signed-off-by:
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Carsten Otte authored
- generic_file* file operations do no longer have a xip/non-xip split - filemap_xip.c implements a new set of fops that require get_xip_page aop to work proper. all new fops are exported GPL-only (don't like to see whatever code use those except GPL modules) - __xip_unmap now uses page_check_address, which is no longer static in rmap.c, and defined in linux/rmap.h - mm/filemap.h is now much more clean, plainly having just Linus' inline funcs moved here from filemap.c - fix includes in filemap_xip to make it build cleanly on i386 Signed-off-by:
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