linux/lib/scatterlist.c, branch v3.16

lib/scatterlist: export sg_miter_skip()

2013-12-09T01:56:37Z

sg_copy_buffer() can't meet demand for some drrivers(such usb mass storage), so we have to use the sg_miter_* APIs to access sg buffer, then need export sg_miter_skip() for these drivers. The API is needed for converting to sg_miter_* APIs in USB storage driver for accessing sg buffer. Acked-by: Andrew Morton Cc: FUJITA Tomonori Cc: Jens Axboe Signed-off-by: Ming Lei Reviewed-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

lib/scatterlist.c: don't flush_kernel_dcache_page on slab page

2013-10-31T23:58:13Z

Commit b1adaf65ba03 ("[SCSI] block: add sg buffer copy helper functions") introduces two sg buffer copy helpers, and calls flush_kernel_dcache_page() on pages in SG list after these pages are written to. Unfortunately, the commit may introduce a potential bug: - Before sending some SCSI commands, kmalloc() buffer may be passed to block layper, so flush_kernel_dcache_page() can see a slab page finally - According to cachetlb.txt, flush_kernel_dcache_page() is only called on "a user page", which surely can't be a slab page. - ARCH's implementation of flush_kernel_dcache_page() may use page mapping information to do optimization so page_mapping() will see the slab page, then VM_BUG_ON() is triggered. Aaro Koskinen reported the bug on ARM/kirkwood when DEBUG_VM is enabled, and this patch fixes the bug by adding test of '!PageSlab(miter->page)' before calling flush_kernel_dcache_page(). Signed-off-by: Ming Lei Reported-by: Aaro Koskinen Tested-by: Simon Baatz Cc: Russell King - ARM Linux Cc: Will Deacon Cc: Aaro Koskinen Acked-by: Catalin Marinas Cc: FUJITA Tomonori Cc: Tejun Heo Cc: "James E.J. Bottomley" Cc: Jens Axboe Cc: [3.2+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/scatterlist: error handling in __sg_alloc_table()

2013-07-09T17:33:31Z

I was reviewing code which I suspected might allocate a zero size SG table. That will cause memory corruption. Also we can't return before doing the memset or we could end up using uninitialized memory in the cleanup path. Signed-off-by: Dan Carpenter Cc: Akinobu Mita Cc: Imre Deak Cc: Tejun Heo Cc: Daniel Vetter Cc: Maxim Levitsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/scatterlist: introduce sg_pcopy_from_buffer() and sg_pcopy_to_buffer()

2013-07-09T17:33:30Z

The only difference between sg_pcopy_{from,to}_buffer() and sg_copy_{from,to}_buffer() is an additional argument that specifies the number of bytes to skip the SG list before copying. Signed-off-by: Akinobu Mita Cc: "David S. Miller" Cc: "James E.J. Bottomley" Cc: Douglas Gilbert Cc: Herbert Xu Cc: Horia Geanta Cc: Imre Deak Acked-by: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/scatterlist: factor out sg_miter_get_next_page() from sg_miter_next()

2013-07-09T17:33:30Z

This patchset introduces sg_pcopy_from_buffer() and sg_pcopy_to_buffer(), which copy data between a linear buffer and an SG list. The only difference between sg_pcopy_{from,to}_buffer() and sg_copy_{from,to}_buffer() is an additional argument that specifies the number of bytes to skip the SG list before copying. The main reason for introducing these functions is to fix a problem in scsi_debug module. And there is a local function in crypto/talitos module, which can be replaced by sg_pcopy_to_buffer(). This patch: sg_miter_get_next_page() is used to proceed page iterator to the next page if necessary, and will be used to implement the variants of sg_copy_{from,to}_buffer() later. Signed-off-by: Akinobu Mita Acked-by: Tejun Heo Cc: Tejun Heo Cc: Imre Deak Cc: Herbert Xu Cc: "David S. Miller" Cc: "James E.J. Bottomley" Cc: Douglas Gilbert Cc: Horia Geanta Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/scatterlist: sg_page_iter: support sg lists w/o backing pages

2013-03-27T16:13:44Z

The i915 driver uses sg lists for memory without backing 'struct page' pages, similarly to other IO memory regions, setting only the DMA address for these. It does this, so that it can program the HW MMU tables in a uniform way both for sg lists with and without backing pages. Without a valid page pointer we can't call nth_page to get the current page in __sg_page_iter_next, so add a helper that relevant users can call separately. Also add a helper to get the DMA address of the current page (idea from Daniel). Convert all places in i915, to use the new API. Signed-off-by: Imre Deak Reviewed-by: Damien Lespiau Signed-off-by: Daniel Vetter

lib/scatterlist: use page iterator in the mapping iterator

2013-02-28T03:10:10Z

For better code reuse use the newly added page iterator to iterate through the pages. The offset, length within the page is still calculated by the mapping iterator as well as the actual mapping. Idea from Tejun Heo. Signed-off-by: Imre Deak Cc: Maxim Levitsky Cc: Tejun Heo Cc: Daniel Vetter Cc: James Hogan Cc: Stephen Warren Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/scatterlist: add simple page iterator

2013-02-28T03:10:10Z

Add an iterator to walk through a scatter list a page at a time starting at a specific page offset. As opposed to the mapping iterator this is meant to be small, performing well even in simple loops like collecting all pages on the scatterlist into an array or setting up an iommu table based on the pages' DMA address. Signed-off-by: Imre Deak Cc: Maxim Levitsky Cc: Tejun Heo Cc: Daniel Vetter Tested-by: Stephen Warren Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

scatterlist: don't BUG when we can trivially return a proper error.

2012-12-18T01:15:28Z

There is absolutely no reason to crash the kernel when we have a perfectly good return value already available to use for conveying failure status. Let's return an error code instead of crashing the kernel: that sounds like a much better plan. [akpm@linux-foundation.org: s/E2BIG/EINVAL/] Signed-off-by: Nick Bowler Cc: Maxim Levitsky Cc: Tejun Heo Cc: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'for-3.7/core' of git://git.kernel.dk/linux-block

2012-10-11T00:04:23Z

Pull block IO update from Jens Axboe: "Core block IO bits for 3.7. Not a huge round this time, it contains: - First series from Kent cleaning up and generalizing bio allocation and freeing. - WRITE_SAME support from Martin. - Mikulas patches to prevent O_DIRECT crashes when someone changes the block size of a device. - Make bio_split() work on data-less bio's (like trim/discards). - A few other minor fixups." Fixed up silent semantic mis-merge as per Mikulas Patocka and Andrew Morton. It is due to the VM no longer using a prio-tree (see commit 6b2dbba8b6ac: "mm: replace vma prio_tree with an interval tree"). So make set_blocksize() use mapping_mapped() instead of open-coding the internal VM knowledge that has changed. * 'for-3.7/core' of git://git.kernel.dk/linux-block: (26 commits) block: makes bio_split support bio without data scatterlist: refactor the sg_nents scatterlist: add sg_nents fs: fix include/percpu-rwsem.h export error percpu-rw-semaphore: fix documentation typos fs/block_dev.c:1644:5: sparse: symbol 'blkdev_mmap' was not declared blockdev: turn a rw semaphore into a percpu rw semaphore Fix a crash when block device is read and block size is changed at the same time block: fix request_queue->flags initialization block: lift the initial queue bypass mode on blk_register_queue() instead of blk_init_allocated_queue() block: ioctl to zero block ranges block: Make blkdev_issue_zeroout use WRITE SAME block: Implement support for WRITE SAME block: Consolidate command flag and queue limit checks for merges block: Clean up special command handling logic block/blk-tag.c: Remove useless kfree block: remove the duplicated setting for congestion_threshold block: reject invalid queue attribute values block: Add bio_clone_bioset(), bio_clone_kmalloc() block: Consolidate bio_alloc_bioset(), bio_kmalloc() ...