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authorLinus Torvalds <torvalds@linux-foundation.org>2020-06-08 11:11:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-08 11:11:38 -0700
commit20b0d06722169e6e66049c8fe6f1a48adffb79c6 (patch)
tree1b88278ca547c07f58297325aea1ab3c447e844d /mm/gup.c
parentvfs: clean up posix_acl_permission() logic aroudn MAY_NOT_BLOCK (diff)
parentdoc: cgroup: update note about conditions when oom killer is invoked (diff)
downloadlinux-dev-20b0d06722169e6e66049c8fe6f1a48adffb79c6.tar.xz
linux-dev-20b0d06722169e6e66049c8fe6f1a48adffb79c6.zip
Merge branch 'akpm' (patches from Andrew)
Merge still more updates from Andrew Morton: "Various trees. Mainly those parts of MM whose linux-next dependents are now merged. I'm still sitting on ~160 patches which await merges from -next. Subsystems affected by this patch series: mm/proc, ipc, dynamic-debug, panic, lib, sysctl, mm/gup, mm/pagemap" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (52 commits) doc: cgroup: update note about conditions when oom killer is invoked module: move the set_fs hack for flush_icache_range to m68k nommu: use flush_icache_user_range in brk and mmap binfmt_flat: use flush_icache_user_range exec: use flush_icache_user_range in read_code exec: only build read_code when needed m68k: implement flush_icache_user_range arm: rename flush_cache_user_range to flush_icache_user_range xtensa: implement flush_icache_user_range sh: implement flush_icache_user_range asm-generic: add a flush_icache_user_range stub mm: rename flush_icache_user_range to flush_icache_user_page arm,sparc,unicore32: remove flush_icache_user_range riscv: use asm-generic/cacheflush.h powerpc: use asm-generic/cacheflush.h openrisc: use asm-generic/cacheflush.h m68knommu: use asm-generic/cacheflush.h microblaze: use asm-generic/cacheflush.h ia64: use asm-generic/cacheflush.h hexagon: use asm-generic/cacheflush.h ...
Diffstat (limited to 'mm/gup.c')
-rw-r--r--mm/gup.c73
1 files changed, 51 insertions, 22 deletions
diff --git a/mm/gup.c b/mm/gup.c
index e19ff770eb4c..8bd090b36d1d 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2035,6 +2035,12 @@ long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
*/
if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
return -EINVAL;
+ /*
+ * FOLL_PIN must only be set internally by the pin_user_pages*() APIs,
+ * never directly by the caller, so enforce that:
+ */
+ if (WARN_ON_ONCE(gup_flags & FOLL_PIN))
+ return -EINVAL;
return __get_user_pages_locked(current, current->mm, start, nr_pages,
pages, NULL, locked,
@@ -2294,7 +2300,7 @@ pte_unmap:
* to be special.
*
* For a futex to be placed on a THP tail page, get_futex_key requires a
- * __get_user_pages_fast implementation that can pin pages. Thus it's still
+ * get_user_pages_fast_only implementation that can pin pages. Thus it's still
* useful to have gup_huge_pmd even if we can't operate on ptes.
*/
static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
@@ -2699,7 +2705,7 @@ static inline void gup_pgd_range(unsigned long addr, unsigned long end,
#ifndef gup_fast_permitted
/*
- * Check if it's allowed to use __get_user_pages_fast() for the range, or
+ * Check if it's allowed to use get_user_pages_fast_only() for the range, or
* we need to fall back to the slow version:
*/
static bool gup_fast_permitted(unsigned long start, unsigned long end)
@@ -2811,8 +2817,14 @@ static int internal_get_user_pages_fast(unsigned long start, int nr_pages,
return ret;
}
-
-/*
+/**
+ * get_user_pages_fast_only() - pin user pages in memory
+ * @start: starting user address
+ * @nr_pages: number of pages from start to pin
+ * @gup_flags: flags modifying pin behaviour
+ * @pages: array that receives pointers to the pages pinned.
+ * Should be at least nr_pages long.
+ *
* Like get_user_pages_fast() except it's IRQ-safe in that it won't fall back to
* the regular GUP.
* Note a difference with get_user_pages_fast: this always returns the
@@ -2825,8 +2837,8 @@ static int internal_get_user_pages_fast(unsigned long start, int nr_pages,
* access can get ambiguous page results. If you call this function without
* 'write' set, you'd better be sure that you're ok with that ambiguity.
*/
-int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
- struct page **pages)
+int get_user_pages_fast_only(unsigned long start, int nr_pages,
+ unsigned int gup_flags, struct page **pages)
{
int nr_pinned;
/*
@@ -2836,10 +2848,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
* FOLL_FAST_ONLY is required in order to match the API description of
* this routine: no fall back to regular ("slow") GUP.
*/
- unsigned int gup_flags = FOLL_GET | FOLL_FAST_ONLY;
-
- if (write)
- gup_flags |= FOLL_WRITE;
+ gup_flags |= FOLL_GET | FOLL_FAST_ONLY;
nr_pinned = internal_get_user_pages_fast(start, nr_pages, gup_flags,
pages);
@@ -2855,7 +2864,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
return nr_pinned;
}
-EXPORT_SYMBOL_GPL(__get_user_pages_fast);
+EXPORT_SYMBOL_GPL(get_user_pages_fast_only);
/**
* get_user_pages_fast() - pin user pages in memory
@@ -2909,9 +2918,6 @@ EXPORT_SYMBOL_GPL(get_user_pages_fast);
*
* FOLL_PIN means that the pages must be released via unpin_user_page(). Please
* see Documentation/core-api/pin_user_pages.rst for further details.
- *
- * This is intended for Case 1 (DIO) in Documentation/core-api/pin_user_pages.rst. It
- * is NOT intended for Case 2 (RDMA: long-term pins).
*/
int pin_user_pages_fast(unsigned long start, int nr_pages,
unsigned int gup_flags, struct page **pages)
@@ -2926,8 +2932,8 @@ int pin_user_pages_fast(unsigned long start, int nr_pages,
EXPORT_SYMBOL_GPL(pin_user_pages_fast);
/*
- * This is the FOLL_PIN equivalent of __get_user_pages_fast(). Behavior is the
- * same, except that this one sets FOLL_PIN instead of FOLL_GET.
+ * This is the FOLL_PIN equivalent of get_user_pages_fast_only(). Behavior
+ * is the same, except that this one sets FOLL_PIN instead of FOLL_GET.
*
* The API rules are the same, too: no negative values may be returned.
*/
@@ -2985,9 +2991,6 @@ EXPORT_SYMBOL_GPL(pin_user_pages_fast_only);
*
* FOLL_PIN means that the pages must be released via unpin_user_page(). Please
* see Documentation/core-api/pin_user_pages.rst for details.
- *
- * This is intended for Case 1 (DIO) in Documentation/core-api/pin_user_pages.rst. It
- * is NOT intended for Case 2 (RDMA: long-term pins).
*/
long pin_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, unsigned long nr_pages,
@@ -3021,9 +3024,6 @@ EXPORT_SYMBOL(pin_user_pages_remote);
*
* FOLL_PIN means that the pages must be released via unpin_user_page(). Please
* see Documentation/core-api/pin_user_pages.rst for details.
- *
- * This is intended for Case 1 (DIO) in Documentation/core-api/pin_user_pages.rst. It
- * is NOT intended for Case 2 (RDMA: long-term pins).
*/
long pin_user_pages(unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages,
@@ -3055,3 +3055,32 @@ long pin_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
return get_user_pages_unlocked(start, nr_pages, pages, gup_flags);
}
EXPORT_SYMBOL(pin_user_pages_unlocked);
+
+/*
+ * pin_user_pages_locked() is the FOLL_PIN variant of get_user_pages_locked().
+ * Behavior is the same, except that this one sets FOLL_PIN and rejects
+ * FOLL_GET.
+ */
+long pin_user_pages_locked(unsigned long start, unsigned long nr_pages,
+ unsigned int gup_flags, struct page **pages,
+ int *locked)
+{
+ /*
+ * FIXME: Current FOLL_LONGTERM behavior is incompatible with
+ * FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on
+ * vmas. As there are no users of this flag in this call we simply
+ * disallow this option for now.
+ */
+ if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
+ return -EINVAL;
+
+ /* FOLL_GET and FOLL_PIN are mutually exclusive. */
+ if (WARN_ON_ONCE(gup_flags & FOLL_GET))
+ return -EINVAL;
+
+ gup_flags |= FOLL_PIN;
+ return __get_user_pages_locked(current, current->mm, start, nr_pages,
+ pages, NULL, locked,
+ gup_flags | FOLL_TOUCH);
+}
+EXPORT_SYMBOL(pin_user_pages_locked);