git: 9bf3a5616c51 - stable/13 - LinuxKPI: add simplified version of page_frag_cache
- Go to: [ bottom of page ] [ top of archives ] [ this month ]
Date: Wed, 18 Jan 2023 16:24:52 UTC
The branch stable/13 has been updated by bz: URL: https://cgit.FreeBSD.org/src/commit/?id=9bf3a5616c51081b221cbb794f559a5aab07aabc commit 9bf3a5616c51081b221cbb794f559a5aab07aabc Author: Bjoern A. Zeeb <bz@FreeBSD.org> AuthorDate: 2022-12-03 00:33:34 +0000 Commit: Bjoern A. Zeeb <bz@FreeBSD.org> CommitDate: 2023-01-18 13:25:11 +0000 LinuxKPI: add simplified version of page_frag_cache For the moment and the currently only consumer (mt76) add a simplified version of the page_frag_cache. We will only accept fragement sizes up to 1 PAGE_SIZE (KASSERT) and we will always return a full page. Should we add more consumers or small (or large) objects would become a problem we can always add a more elaborate version. Discussed with: markj Reviewed by: markj (,hselasky commented as well) MFC after: 3 days Differential Revision: https://reviews.freebsd.org/D37595 (cherry picked from commit 55038a6306a570c9f2df89f5ad076de0f7d98152) LinuxKPI: fix possible NULL dereference in linuxkpi_page_frag_alloc() Reported by: Coverity via emaste Coverity ID: 1502345 Sponsored by: The FreeBSD Foundation (cherry picked from commit 51e94a4658d23016dd0ae67c189a89f53281cbcd) --- sys/compat/linuxkpi/common/include/linux/gfp.h | 29 ++++++++++++++++ sys/compat/linuxkpi/common/src/linux_page.c | 47 ++++++++++++++++++++++++++ 2 files changed, 76 insertions(+) diff --git a/sys/compat/linuxkpi/common/include/linux/gfp.h b/sys/compat/linuxkpi/common/include/linux/gfp.h index 6273fa969db8..7657e78b0950 100644 --- a/sys/compat/linuxkpi/common/include/linux/gfp.h +++ b/sys/compat/linuxkpi/common/include/linux/gfp.h @@ -80,6 +80,11 @@ CTASSERT((__GFP_DMA32 & GFP_NATIVE_MASK) == 0); CTASSERT((__GFP_BITS_MASK & GFP_NATIVE_MASK) == GFP_NATIVE_MASK); +struct page_frag_cache { + void *va; + int pagecnt_bias; +}; + /* * Resolve a page into a virtual address: * @@ -94,6 +99,9 @@ extern void *linux_page_address(struct page *); */ extern vm_page_t linux_alloc_pages(gfp_t flags, unsigned int order); extern void linux_free_pages(vm_page_t page, unsigned int order); +void *linuxkpi_page_frag_alloc(struct page_frag_cache *, size_t, gfp_t); +void linuxkpi_page_frag_free(void *); +void linuxkpi__page_frag_cache_drain(struct page *, size_t); static inline struct page * alloc_page(gfp_t flags) @@ -175,6 +183,27 @@ free_page(uintptr_t addr) linux_free_kmem(addr, 0); } +static inline void * +page_frag_alloc(struct page_frag_cache *pfc, size_t fragsz, gfp_t gfp) +{ + + return (linuxkpi_page_frag_alloc(pfc, fragsz, gfp)); +} + +static inline void +page_frag_free(void *addr) +{ + + linuxkpi_page_frag_free(addr); +} + +static inline void +__page_frag_cache_drain(struct page *page, size_t count) +{ + + linuxkpi__page_frag_cache_drain(page, count); +} + static inline bool gfpflags_allow_blocking(const gfp_t gfp_flags) { diff --git a/sys/compat/linuxkpi/common/src/linux_page.c b/sys/compat/linuxkpi/common/src/linux_page.c index df4a124cf3e2..5fa370147045 100644 --- a/sys/compat/linuxkpi/common/src/linux_page.c +++ b/sys/compat/linuxkpi/common/src/linux_page.c @@ -429,3 +429,50 @@ lkpi_arch_phys_wc_del(int reg) free(mrdesc, M_LKMTRR); #endif } + +/* + * This is a highly simplified version of the Linux page_frag_cache. + * We only support up-to 1 single page as fragment size and we will + * always return a full page. This may be wasteful on small objects + * but the only known consumer (mt76) is either asking for a half-page + * or a full page. If this was to become a problem we can implement + * a more elaborate version. + */ +void * +linuxkpi_page_frag_alloc(struct page_frag_cache *pfc, + size_t fragsz, gfp_t gfp) +{ + vm_page_t pages; + + if (fragsz == 0) + return (NULL); + + KASSERT(fragsz <= PAGE_SIZE, ("%s: fragsz %zu > PAGE_SIZE not yet " + "supported", __func__, fragsz)); + + pages = alloc_pages(gfp, flsl(howmany(fragsz, PAGE_SIZE) - 1)); + if (pages == NULL) + return (NULL); + pfc->va = linux_page_address(pages); + + /* Passed in as "count" to __page_frag_cache_drain(). Unused by us. */ + pfc->pagecnt_bias = 0; + + return (pfc->va); +} + +void +linuxkpi_page_frag_free(void *addr) +{ + vm_page_t page; + + page = PHYS_TO_VM_PAGE(vtophys(addr)); + linux_free_pages(page, 0); +} + +void +linuxkpi__page_frag_cache_drain(struct page *page, size_t count __unused) +{ + + linux_free_pages(page, 0); +}