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2016-04-04mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macrosKirill A. Shutemov1-2/+2
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-20Squashfs: Generalise paging handling in the decompressorsPhillip Lougher1-9/+13
Further generalise the decompressors by adding a page handler abstraction. This adds helpers to allow the decompressors to access and process the output buffers in an implementation independant manner. This allows different types of output buffer to be passed to the decompressors, with the implementation specific aspects handled at decompression time, but without the knowledge being held in the decompressor wrapper code. This will allow the decompressors to handle Squashfs cache buffers, and page cache pages. This patch adds the abstraction and an implementation for the caches. Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk> Reviewed-by: Minchan Kim <minchan@kernel.org>
2013-11-20Squashfs: Refactor decompressor interface and codePhillip Lougher1-40/+49
The decompressor interface and code was written from the point of view of single-threaded operation. In doing so it mixed a lot of single-threaded implementation specific aspects into the decompressor code and elsewhere which makes it difficult to seamlessly support multiple different decompressor implementations. This patch does the following: 1. It removes compressor_options parsing from the decompressor init() function. This allows the decompressor init() function to be dynamically called to instantiate multiple decompressors, without the compressor options needing to be read and parsed each time. 2. It moves threading and all sleeping operations out of the decompressors. In doing so, it makes the decompressors non-blocking wrappers which only deal with interfacing with the decompressor implementation. 3. It splits decompressor.[ch] into decompressor generic functions in decompressor.[ch], and moves the single threaded decompressor implementation into decompressor_single.c. The result of this patch is Squashfs should now be able to support multiple decompressors by adding new decompressor_xxx.c files with specialised implementations of the functions in decompressor_single.c Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk> Reviewed-by: Minchan Kim <minchan@kernel.org>
2011-05-26Squashfs: update email addressPhillip Lougher1-1/+1
My existing email address may stop working in a month or two, so update email to one that will continue working. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2011-02-28Squashfs: xz_wrapper doesn't need to include squashfs_fs_i.h anymorePhillip Lougher1-1/+0
Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2011-02-28Squashfs: add compression options support to xz decompressorPhillip Lougher1-8/+41
Pass the dictionary size used to compress datablocks. Using a dictionary size less than the block size saves memory overhead, in many cases without adversely affecting compression ratio. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2011-02-28Squashfs: extend decompressor framework to handle compression optionsPhillip Lougher1-2/+3
Extend decompressor framework to handle compression options stored in the filesystem. These options can be used by the relevant decompressor at initialisation time to over-ride defaults. The presence of compression options in the filesystem is indicated by the COMP_OPT filesystem flag. If present the data is read from the filesystem and passed to the decompressor init function. The decompressor init function signature has been extended to take this data. Also update the init function signature in the glib, lzo and xz decompressor wrappers. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2011-01-26squashfs: fix use of uninitialised variable in zlib & xz decompressorsPhillip Lougher1-6/+0
Fix potential use of uninitialised variable caused by recent decompressor code optimisations. In zlib_uncompress (zlib_wrapper.c) we have int zlib_err, zlib_init = 0; ... do { ... if (avail == 0) { offset = 0; put_bh(bh[k++]); continue; } ... zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH); ... } while (zlib_err == Z_OK); If continue is executed (avail == 0) then the while condition will be evaluated testing zlib_err, which is uninitialised first time around the loop. Fix this by getting rid of the 'if (avail == 0)' condition test, this edge condition should not be being handled in the decompressor code, and instead handle it generically in the caller code. Similarly for xz_wrapper.c. Incidentally, on most architectures (bar Mips and Parisc), no uninitialised variable warning is generated by gcc, this is because the while condition test on continue is optimised out and not performed (when executing continue zlib_err has not been changed since entering the loop, and logically if the while condition was true previously, then it's still true). Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk> Reported-by: Jesper Juhl <jj@chaosbits.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13Squashfs: add XZ compression supportPhillip Lougher1-0/+153
Add support for reading file systems compressed with the XZ compression algorithm. This patch adds the XZ decompressor wrapper code. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>