Commit ba836a6f authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'akpm' (patches from Andrew) 

Merge fixes from Andrew Morton:
 "27 fixes.

  There are three patches that aren't actually fixes. They're simple
  function renamings which are nice-to-have in mainline as ongoing net
  development depends on them."

* akpm: (27 commits)
  timerfd: export defines to userspace
  mm/hugetlb.c: fix reservation race when freeing surplus pages
  mm/slab.c: fix SLAB freelist randomization duplicate entries
  zram: support BDI_CAP_STABLE_WRITES
  zram: revalidate disk under init_lock
  mm: support anonymous stable page
  mm: add documentation for page fragment APIs
  mm: rename __page_frag functions to __page_frag_cache, drop order from drain
  mm: rename __alloc_page_frag to page_frag_alloc and __free_page_frag to page_frag_free
  mm, memcg: fix the active list aging for lowmem requests when memcg is enabled
  mm: don't dereference struct page fields of invalid pages
  mailmap: add codeaurora.org names for nameless email commits
  signal: protect SIGNAL_UNKILLABLE from unintentional clearing.
  mm: pmd dirty emulation in page fault handler
  ipc/sem.c: fix incorrect sem_lock pairing
  lib/Kconfig.debug: fix frv build failure
  mm: get rid of __GFP_OTHER_NODE
  mm: fix remote numa hits statistics
  mm: fix devm_memremap_pages crash, use mem_hotplug_{begin, done}
  ocfs2: fix crash caused by stale lvb with fsdlm plugin
  ...
parents cff3b2c4 575b1967

.mailmap

+4 −0
Original line number Diff line number Diff line
@@ -137,6 +137,7 @@ Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> 
Rudolf Marek <R.Marek@sh.cvut.cz>

Rui Saraiva <rmps@joel.ist.utl.pt>

Sachin P Sant <ssant@in.ibm.com>

Sarangdhar Joshi <spjoshi@codeaurora.org>

Sam Ravnborg <sam@mars.ravnborg.org>

Santosh Shilimkar <ssantosh@kernel.org>

Santosh Shilimkar <santosh.shilimkar@oracle.org>
@@ -150,10 +151,13 @@ Shuah Khan <shuah@kernel.org> <shuah.kh@samsung.com> 
Simon Kelley <simon@thekelleys.org.uk>

Stéphane Witzmann <stephane.witzmann@ubpmes.univ-bpclermont.fr>

Stephen Hemminger <shemminger@osdl.org>

Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>

Subhash Jadavani <subhashj@codeaurora.org>

Sudeep Holla <sudeep.holla@arm.com> Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>

Sumit Semwal <sumit.semwal@ti.com>

Tejun Heo <htejun@gmail.com>

Thomas Graf <tgraf@suug.ch>

Thomas Pedersen <twp@codeaurora.org>

Tony Luck <tony.luck@intel.com>

Tsuneo Yoshioka <Tsuneo.Yoshioka@f-secure.com>

Uwe Kleine-König <ukleinek@informatik.uni-freiburg.de>

Documentation/vm/page_frags

0 → 100644
+42 −0
Original line number Diff line number Diff line 
Page fragments

--------------



A page fragment is an arbitrary-length arbitrary-offset area of memory

which resides within a 0 or higher order compound page.  Multiple

fragments within that page are individually refcounted, in the page's

reference counter.



The page_frag functions, page_frag_alloc and page_frag_free, provide a

simple allocation framework for page fragments.  This is used by the

network stack and network device drivers to provide a backing region of

memory for use as either an sk_buff->head, or to be used in the "frags"

portion of skb_shared_info.



In order to make use of the page fragment APIs a backing page fragment

cache is needed.  This provides a central point for the fragment allocation

and tracks allows multiple calls to make use of a cached page.  The

advantage to doing this is that multiple calls to get_page can be avoided

which can be expensive at allocation time.  However due to the nature of

this caching it is required that any calls to the cache be protected by

either a per-cpu limitation, or a per-cpu limitation and forcing interrupts

to be disabled when executing the fragment allocation.



The network stack uses two separate caches per CPU to handle fragment

allocation.  The netdev_alloc_cache is used by callers making use of the

__netdev_alloc_frag and __netdev_alloc_skb calls.  The napi_alloc_cache is

used by callers of the __napi_alloc_frag and __napi_alloc_skb calls.  The

main difference between these two calls is the context in which they may be

called.  The "netdev" prefixed functions are usable in any context as these

functions will disable interrupts, while the "napi" prefixed functions are

only usable within the softirq context.



Many network device drivers use a similar methodology for allocating page

fragments, but the page fragments are cached at the ring or descriptor

level.  In order to enable these cases it is necessary to provide a generic

way of tearing down a page cache.  For this reason __page_frag_cache_drain

was implemented.  It allows for freeing multiple references from a single

page via a single call.  The advantage to doing this is that it allows for

cleaning up the multiple references that were added to a page in order to

avoid calling get_page per allocation.



Alexander Duyck, Nov 29, 2016.

MAINTAINERS

+0 −1
Original line number Diff line number Diff line
@@ -81,7 +81,6 @@ Descriptions of section entries: 
	Q: Patchwork web based patch tracking system site

	T: SCM tree type and location.

	   Type is one of: git, hg, quilt, stgit, topgit

	B: Bug tracking system location.

	S: Status, one of the following:

	   Supported:	Someone is actually paid to look after this.

	   Maintained:	Someone actually looks after it.

drivers/block/zram/zram_drv.c

+11 −8
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <linux/genhd.h>

#include <linux/highmem.h>

#include <linux/slab.h>

#include <linux/backing-dev.h>

#include <linux/string.h>

#include <linux/vmalloc.h>

#include <linux/err.h>
@@ -112,6 +113,14 @@ static inline bool is_partial_io(struct bio_vec *bvec) 
	return bvec->bv_len != PAGE_SIZE;

}



static void zram_revalidate_disk(struct zram *zram)

{

	revalidate_disk(zram->disk);

	/* revalidate_disk reset the BDI_CAP_STABLE_WRITES so set again */

	zram->disk->queue->backing_dev_info.capabilities |=

		BDI_CAP_STABLE_WRITES;

}



/*

 * Check if request is within bounds and aligned on zram logical blocks.

 */
@@ -1095,15 +1104,9 @@ static ssize_t disksize_store(struct device *dev, 
	zram->comp = comp;

	zram->disksize = disksize;

	set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);

	zram_revalidate_disk(zram);

	up_write(&zram->init_lock);



	/*

	 * Revalidate disk out of the init_lock to avoid lockdep splat.

	 * It's okay because disk's capacity is protected by init_lock

	 * so that revalidate_disk always sees up-to-date capacity.

	 */

	revalidate_disk(zram->disk);



	return len;



out_destroy_comp:
@@ -1149,7 +1152,7 @@ static ssize_t reset_store(struct device *dev, 
	/* Make sure all the pending I/O are finished */

	fsync_bdev(bdev);

	zram_reset_device(zram);

	revalidate_disk(zram->disk);

	zram_revalidate_disk(zram);

	bdput(bdev);



	mutex_lock(&bdev->bd_mutex);

drivers/net/ethernet/intel/igb/igb_main.c

+3 −3
Original line number Diff line number Diff line
@@ -3962,7 +3962,7 @@ static void igb_clean_rx_ring(struct igb_ring *rx_ring) 
				     PAGE_SIZE,

				     DMA_FROM_DEVICE,

				     DMA_ATTR_SKIP_CPU_SYNC);

		__page_frag_drain(buffer_info->page, 0,

		__page_frag_cache_drain(buffer_info->page,

					buffer_info->pagecnt_bias);



		buffer_info->page = NULL;
@@ -6991,7 +6991,7 @@ static struct sk_buff *igb_fetch_rx_buffer(struct igb_ring *rx_ring, 
		dma_unmap_page_attrs(rx_ring->dev, rx_buffer->dma,

				     PAGE_SIZE, DMA_FROM_DEVICE,

				     DMA_ATTR_SKIP_CPU_SYNC);

		__page_frag_drain(page, 0, rx_buffer->pagecnt_bias);

		__page_frag_cache_drain(page, rx_buffer->pagecnt_bias);

	}



	/* clear contents of rx_buffer */

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