The patch titled Subject: mm: add get_kernel_page[s] for pinning of kernel addresses for I/O has been added to the -mm tree. Its filename is mm-add-get_kernel_page-for-pinning-of-kernel-addresses-for-i-o.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Mel Gorman <mgorman@xxxxxxx> Subject: mm: add get_kernel_page[s] for pinning of kernel addresses for I/O This patch adds two new APIs get_kernel_pages() and get_kernel_page() that may be used to pin a vector of kernel addresses for IO. The initial user is expected to be NFS for allowing pages to be written to swap using aops->direct_IO(). Strictly speaking, swap-over-NFS only needs to pin one page for IO but it makes sense to express the API in terms of a vector and add a helper for pinning single pages. Signed-off-by: Mel Gorman <mgorman@xxxxxxx> Reviewed-by: Rik van Riel <riel@xxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> Cc: David S. Miller <davem@xxxxxxxxxxxxx> Cc: Eric B Munson <emunson@xxxxxxxxx> Cc: Eric Paris <eparis@xxxxxxxxxx> Cc: James Morris <jmorris@xxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxx> Cc: Mike Christie <michaelc@xxxxxxxxxxx> Cc: Neil Brown <neilb@xxxxxxx> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Cc: Sebastian Andrzej Siewior <sebastian@xxxxxxxxxxxxx> Cc: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx> Cc: Xiaotian Feng <dfeng@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/blk_types.h | 2 + include/linux/fs.h | 2 + include/linux/mm.h | 4 ++ mm/memory.c | 53 ++++++++++++++++++++++++++++++++++++ 4 files changed, 61 insertions(+) diff -puN include/linux/blk_types.h~mm-add-get_kernel_page-for-pinning-of-kernel-addresses-for-i-o include/linux/blk_types.h --- a/include/linux/blk_types.h~mm-add-get_kernel_page-for-pinning-of-kernel-addresses-for-i-o +++ a/include/linux/blk_types.h @@ -160,6 +160,7 @@ enum rq_flag_bits { __REQ_FLUSH_SEQ, /* request for flush sequence */ __REQ_IO_STAT, /* account I/O stat */ __REQ_MIXED_MERGE, /* merge of different types, fail separately */ + __REQ_KERNEL, /* direct IO to kernel pages */ __REQ_NR_BITS, /* stops here */ }; @@ -201,5 +202,6 @@ enum rq_flag_bits { #define REQ_IO_STAT (1 << __REQ_IO_STAT) #define REQ_MIXED_MERGE (1 << __REQ_MIXED_MERGE) #define REQ_SECURE (1 << __REQ_SECURE) +#define REQ_KERNEL (1 << __REQ_KERNEL) #endif /* __LINUX_BLK_TYPES_H */ diff -puN include/linux/fs.h~mm-add-get_kernel_page-for-pinning-of-kernel-addresses-for-i-o include/linux/fs.h --- a/include/linux/fs.h~mm-add-get_kernel_page-for-pinning-of-kernel-addresses-for-i-o +++ a/include/linux/fs.h @@ -165,6 +165,8 @@ struct inodes_stat_t { #define READ 0 #define WRITE RW_MASK #define READA RWA_MASK +#define KERNEL_READ (READ|REQ_KERNEL) +#define KERNEL_WRITE (WRITE|REQ_KERNEL) #define READ_SYNC (READ | REQ_SYNC) #define WRITE_SYNC (WRITE | REQ_SYNC | REQ_NOIDLE) diff -puN include/linux/mm.h~mm-add-get_kernel_page-for-pinning-of-kernel-addresses-for-i-o include/linux/mm.h --- a/include/linux/mm.h~mm-add-get_kernel_page-for-pinning-of-kernel-addresses-for-i-o +++ a/include/linux/mm.h @@ -1019,6 +1019,10 @@ int get_user_pages(struct task_struct *t struct page **pages, struct vm_area_struct **vmas); int get_user_pages_fast(unsigned long start, int nr_pages, int write, struct page **pages); +struct kvec; +int get_kernel_pages(const struct kvec *iov, int nr_pages, int write, + struct page **pages); +int get_kernel_page(unsigned long start, int write, struct page **pages); struct page *get_dump_page(unsigned long addr); extern int try_to_release_page(struct page * page, gfp_t gfp_mask); diff -puN mm/memory.c~mm-add-get_kernel_page-for-pinning-of-kernel-addresses-for-i-o mm/memory.c --- a/mm/memory.c~mm-add-get_kernel_page-for-pinning-of-kernel-addresses-for-i-o +++ a/mm/memory.c @@ -1843,6 +1843,59 @@ next_page: EXPORT_SYMBOL(__get_user_pages); /* + * get_kernel_pages() - pin kernel pages in memory + * @kiov: An array of struct kvec structures + * @nr_segs: number of segments to pin + * @write: pinning for read/write, currently ignored + * @pages: array that receives pointers to the pages pinned. + * Should be at least nr_segs long. + * + * Returns number of pages pinned. This may be fewer than the number + * requested. If nr_pages is 0 or negative, returns 0. If no pages + * were pinned, returns -errno. Each page returned must be released + * with a put_page() call when it is finished with. + */ +int get_kernel_pages(const struct kvec *kiov, int nr_segs, int write, + struct page **pages) +{ + int seg; + + for (seg = 0; seg < nr_segs; seg++) { + if (WARN_ON(kiov[seg].iov_len != PAGE_SIZE)) + return seg; + + /* virt_to_page sanity checks the PFN */ + pages[seg] = virt_to_page(kiov[seg].iov_base); + page_cache_get(pages[seg]); + } + + return seg; +} +EXPORT_SYMBOL_GPL(get_kernel_pages); + +/* + * get_kernel_page() - pin a kernel page in memory + * @start: starting kernel address + * @write: pinning for read/write, currently ignored + * @pages: array that receives pointer to the page pinned. + * Must be at least nr_segs long. + * + * Returns 1 if page is pinned. If the page was not pinned, returns + * -errno. The page returned must be released with a put_page() call + * when it is finished with. + */ +int get_kernel_page(unsigned long start, int write, struct page **pages) +{ + const struct kvec kiov = { + .iov_base = (void *)start, + .iov_len = PAGE_SIZE + }; + + return get_kernel_pages(&kiov, 1, write, pages); +} +EXPORT_SYMBOL_GPL(get_kernel_page); + +/* * fixup_user_fault() - manually resolve a user page fault * @tsk: the task_struct to use for page fault accounting, or * NULL if faults are not to be recorded. _ Subject: Subject: mm: add get_kernel_page[s] for pinning of kernel addresses for I/O Patches currently in -mm which might be from mgorman@xxxxxxx are origin.patch linux-next.patch memcg-prevent-oom-with-too-many-dirty-pages.patch memcg-prevent-oom-with-too-many-dirty-pages-fix.patch mm-do-not-use-page_count-without-a-page-pin.patch mm-clean-up-__count_immobile_pages.patch mm-hotplug-correctly-setup-fallback-zonelists-when-creating-new-pgdat.patch mm-hotplug-correctly-add-new-zone-to-all-other-nodes-zone-lists.patch mm-hotplug-free-zone-pageset-when-a-zone-becomes-empty.patch mm-hotplug-mark-memory-hotplug-code-in-page_allocc-as-__meminit.patch mm-factor-out-memory-isolate-functions.patch mm-bug-fix-free-page-check-in-zone_watermark_ok.patch memory-hotplug-fix-kswapd-looping-forever-problem.patch memory-hotplug-fix-kswapd-looping-forever-problem-fix.patch mm-slb-add-knowledge-of-pfmemalloc-reserve-pages.patch mm-slub-optimise-the-slub-fast-path-to-avoid-pfmemalloc-checks.patch mm-introduce-__gfp_memalloc-to-allow-access-to-emergency-reserves.patch mm-allow-pf_memalloc-from-softirq-context.patch mm-only-set-page-pfmemalloc-when-alloc_no_watermarks-was-used.patch mm-ignore-mempolicies-when-using-alloc_no_watermark.patch net-introduce-sk_gfp_atomic-to-allow-addition-of-gfp-flags-depending-on-the-individual-socket.patch netvm-allow-the-use-of-__gfp_memalloc-by-specific-sockets.patch netvm-allow-skb-allocation-to-use-pfmemalloc-reserves.patch netvm-propagate-page-pfmemalloc-to-skb.patch netvm-propagate-page-pfmemalloc-from-skb_alloc_page-to-skb.patch netvm-set-pf_memalloc-as-appropriate-during-skb-processing.patch mm-micro-optimise-slab-to-avoid-a-function-call.patch nbd-set-sock_memalloc-for-access-to-pfmemalloc-reserves.patch mm-throttle-direct-reclaimers-if-pf_memalloc-reserves-are-low-and-swap-is-backed-by-network-storage.patch mm-account-for-the-number-of-times-direct-reclaimers-get-throttled.patch netvm-prevent-a-stream-specific-deadlock.patch selinux-tag-avc-cache-alloc-as-non-critical.patch mm-methods-for-teaching-filesystems-about-pg_swapcache-pages.patch mm-add-support-for-a-filesystem-to-activate-swap-files-and-use-direct_io-for-writing-swap-pages.patch mm-swap-implement-generic-handler-for-swap_activate.patch mm-add-get_kernel_page-for-pinning-of-kernel-addresses-for-i-o.patch mm-add-support-for-direct_io-to-highmem-pages.patch nfs-teach-the-nfs-client-how-to-treat-pg_swapcache-pages.patch nfs-disable-data-cache-revalidation-for-swapfiles.patch nfs-enable-swap-on-nfs.patch nfs-prevent-page-allocator-recursions-with-swap-over-nfs.patch swapfile-avoid-dereferencing-bd_disk-during-swap_entry_free-for-network-storage.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html