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authorMike Kravetz <mike.kravetz@oracle.com>2023-06-08 13:49:27 -0700
committerAndrew Morton <akpm@linux-foundation.org>2023-06-19 13:19:32 -0700
commitb7cb3821905b79b6ed474fd5ba34d1e187649139 (patch)
tree6e3eb491fed45ff62bcacf7fbab4e8a65fd728db /drivers/dma-buf
parentc8a8f3b4a95ace7683b615ad9c9aa0eac59013ae (diff)
udmabuf: revert 'Add support for mapping hugepages (v4)'
This effectively reverts commit 16c243e99d33 ("udmabuf: Add support for mapping hugepages (v4)"). Recently, Junxiao Chang found a BUG with page map counting as described here [1]. This issue pointed out that the udmabuf driver was making direct use of subpages of hugetlb pages. This is not a good idea, and no other mm code attempts such use. In addition to the mapcount issue, this also causes issues with hugetlb vmemmap optimization and page poisoning. For now, remove hugetlb support. If udmabuf wants to be used on hugetlb mappings, it should be changed to only use complete hugetlb pages. This will require different alignment and size requirements on the UDMABUF_CREATE API. [1] https://lore.kernel.org/linux-mm/20230512072036.1027784-1-junxiao.chang@intel.com/ Link: https://lkml.kernel.org/r/20230608204927.88711-1-mike.kravetz@oracle.com Fixes: 16c243e99d33 ("udmabuf: Add support for mapping hugepages (v4)") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Vivek Kasireddy <vivek.kasireddy@intel.com> Acked-by: Gerd Hoffmann <kraxel@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Dongwon Kim <dongwon.kim@intel.com> Cc: James Houghton <jthoughton@google.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Junxiao Chang <junxiao.chang@intel.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'drivers/dma-buf')
-rw-r--r--drivers/dma-buf/udmabuf.c47
1 files changed, 6 insertions, 41 deletions
diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index 01f2e86f3f7c..12cf6bb2e3ce 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -12,7 +12,6 @@
#include <linux/shmem_fs.h>
#include <linux/slab.h>
#include <linux/udmabuf.h>
-#include <linux/hugetlb.h>
#include <linux/vmalloc.h>
#include <linux/iosys-map.h>
@@ -207,9 +206,7 @@ static long udmabuf_create(struct miscdevice *device,
struct udmabuf *ubuf;
struct dma_buf *buf;
pgoff_t pgoff, pgcnt, pgidx, pgbuf = 0, pglimit;
- struct page *page, *hpage = NULL;
- pgoff_t subpgoff, maxsubpgs;
- struct hstate *hpstate;
+ struct page *page;
int seals, ret = -EINVAL;
u32 i, flags;
@@ -245,7 +242,7 @@ static long udmabuf_create(struct miscdevice *device,
if (!memfd)
goto err;
mapping = memfd->f_mapping;
- if (!shmem_mapping(mapping) && !is_file_hugepages(memfd))
+ if (!shmem_mapping(mapping))
goto err;
seals = memfd_fcntl(memfd, F_GET_SEALS, 0);
if (seals == -EINVAL)
@@ -256,48 +253,16 @@ static long udmabuf_create(struct miscdevice *device,
goto err;
pgoff = list[i].offset >> PAGE_SHIFT;
pgcnt = list[i].size >> PAGE_SHIFT;
- if (is_file_hugepages(memfd)) {
- hpstate = hstate_file(memfd);
- pgoff = list[i].offset >> huge_page_shift(hpstate);
- subpgoff = (list[i].offset &
- ~huge_page_mask(hpstate)) >> PAGE_SHIFT;
- maxsubpgs = huge_page_size(hpstate) >> PAGE_SHIFT;
- }
for (pgidx = 0; pgidx < pgcnt; pgidx++) {
- if (is_file_hugepages(memfd)) {
- if (!hpage) {
- hpage = find_get_page_flags(mapping, pgoff,
- FGP_ACCESSED);
- if (!hpage) {
- ret = -EINVAL;
- goto err;
- }
- }
- page = hpage + subpgoff;
- get_page(page);
- subpgoff++;
- if (subpgoff == maxsubpgs) {
- put_page(hpage);
- hpage = NULL;
- subpgoff = 0;
- pgoff++;
- }
- } else {
- page = shmem_read_mapping_page(mapping,
- pgoff + pgidx);
- if (IS_ERR(page)) {
- ret = PTR_ERR(page);
- goto err;
- }
+ page = shmem_read_mapping_page(mapping, pgoff + pgidx);
+ if (IS_ERR(page)) {
+ ret = PTR_ERR(page);
+ goto err;
}
ubuf->pages[pgbuf++] = page;
}
fput(memfd);
memfd = NULL;
- if (hpage) {
- put_page(hpage);
- hpage = NULL;
- }
}
exp_info.ops = &udmabuf_ops;