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authorLorenzo Stoakes <lstoakes@gmail.com>2023-05-17 22:25:39 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-06-10 02:25:26 +0300
commitca5e863233e8f6acd1792fd85d6bc2729a1b2c10 (patch)
tree6414634aa510193333853625a260aad4b68f7770 /mm/gup.c
parent0b295316b3a9b7858eafbebdc31b4827a6edde03 (diff)
downloadlinux-ca5e863233e8f6acd1792fd85d6bc2729a1b2c10.tar.xz
mm/gup: remove vmas parameter from get_user_pages_remote()
The only instances of get_user_pages_remote() invocations which used the vmas parameter were for a single page which can instead simply look up the VMA directly. In particular:- - __update_ref_ctr() looked up the VMA but did nothing with it so we simply remove it. - __access_remote_vm() was already using vma_lookup() when the original lookup failed so by doing the lookup directly this also de-duplicates the code. We are able to perform these VMA operations as we already hold the mmap_lock in order to be able to call get_user_pages_remote(). As part of this work we add get_user_page_vma_remote() which abstracts the VMA lookup, error handling and decrementing the page reference count should the VMA lookup fail. This forms part of a broader set of patches intended to eliminate the vmas parameter altogether. [akpm@linux-foundation.org: avoid passing NULL to PTR_ERR] Link: https://lkml.kernel.org/r/d20128c849ecdbf4dd01cc828fcec32127ed939a.1684350871.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> (for arm64) Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com> (for s390) Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Christian König <christian.koenig@amd.com> Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jarkko Sakkinen <jarkko@kernel.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Sakari Ailus <sakari.ailus@linux.intel.com> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/gup.c')
-rw-r--r--mm/gup.c12
1 files changed, 4 insertions, 8 deletions
diff --git a/mm/gup.c b/mm/gup.c
index edf0fe2695b0..764bf0c20827 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2165,8 +2165,6 @@ static bool is_valid_gup_args(struct page **pages, struct vm_area_struct **vmas,
* @pages: array that receives pointers to the pages pinned.
* Should be at least nr_pages long. Or NULL, if caller
* only intends to ensure the pages are faulted in.
- * @vmas: array of pointers to vmas corresponding to each page.
- * Or NULL if the caller does not require them.
* @locked: pointer to lock flag indicating whether lock is held and
* subsequently whether VM_FAULT_RETRY functionality can be
* utilised. Lock must initially be held.
@@ -2181,8 +2179,6 @@ static bool is_valid_gup_args(struct page **pages, struct vm_area_struct **vmas,
*
* The caller is responsible for releasing returned @pages, via put_page().
*
- * @vmas are valid only as long as mmap_lock is held.
- *
* Must be called with mmap_lock held for read or write.
*
* get_user_pages_remote walks a process's page tables and takes a reference
@@ -2219,15 +2215,15 @@ static bool is_valid_gup_args(struct page **pages, struct vm_area_struct **vmas,
long get_user_pages_remote(struct mm_struct *mm,
unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas, int *locked)
+ int *locked)
{
int local_locked = 1;
- if (!is_valid_gup_args(pages, vmas, locked, &gup_flags,
+ if (!is_valid_gup_args(pages, NULL, locked, &gup_flags,
FOLL_TOUCH | FOLL_REMOTE))
return -EINVAL;
- return __get_user_pages_locked(mm, start, nr_pages, pages, vmas,
+ return __get_user_pages_locked(mm, start, nr_pages, pages, NULL,
locked ? locked : &local_locked,
gup_flags);
}
@@ -2237,7 +2233,7 @@ EXPORT_SYMBOL(get_user_pages_remote);
long get_user_pages_remote(struct mm_struct *mm,
unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas, int *locked)
+ int *locked)
{
return 0;
}