diff options
Diffstat (limited to 'module/zfs/abd.c')
| -rw-r--r-- | module/zfs/abd.c | 94 |
1 files changed, 25 insertions, 69 deletions
diff --git a/module/zfs/abd.c b/module/zfs/abd.c index c8c4d2270..529deeecf 100644 --- a/module/zfs/abd.c +++ b/module/zfs/abd.c @@ -89,8 +89,8 @@ * functions. * * As an additional feature, linear and scatter ABD's can be stitched together - * by using the gang ABD type (abd_alloc_gang_abd()). This allows for - * multiple ABDs to be viewed as a singular ABD. + * by using the gang ABD type (abd_alloc_gang()). This allows for multiple ABDs + * to be viewed as a singular ABD. * * It is possible to make all ABDs linear by setting zfs_abd_scatter_enabled to * B_FALSE. @@ -109,11 +109,15 @@ void abd_verify(abd_t *abd) { #ifdef ZFS_DEBUG - ASSERT3U(abd->abd_size, <=, SPA_MAXBLOCKSIZE); + if (abd_is_from_pages(abd)) { + ASSERT3U(abd->abd_size, <=, DMU_MAX_ACCESS); + } else { + ASSERT3U(abd->abd_size, <=, SPA_MAXBLOCKSIZE); + } ASSERT3U(abd->abd_flags, ==, abd->abd_flags & (ABD_FLAG_LINEAR | ABD_FLAG_OWNER | ABD_FLAG_META | ABD_FLAG_MULTI_ZONE | ABD_FLAG_MULTI_CHUNK | ABD_FLAG_LINEAR_PAGE | ABD_FLAG_GANG | - ABD_FLAG_GANG_FREE | ABD_FLAG_ALLOCD)); + ABD_FLAG_GANG_FREE | ABD_FLAG_ALLOCD | ABD_FLAG_FROM_PAGES)); IMPLY(abd->abd_parent != NULL, !(abd->abd_flags & ABD_FLAG_OWNER)); IMPLY(abd->abd_flags & ABD_FLAG_META, abd->abd_flags & ABD_FLAG_OWNER); if (abd_is_linear(abd)) { @@ -136,7 +140,7 @@ abd_verify(abd_t *abd) #endif } -static void +void abd_init_struct(abd_t *abd) { list_link_init(&abd->abd_gang_link); @@ -238,6 +242,7 @@ abd_free_linear(abd_t *abd) abd_free_linear_page(abd); return; } + if (abd->abd_flags & ABD_FLAG_META) { zio_buf_free(ABD_LINEAR_BUF(abd), abd->abd_size); } else { @@ -520,6 +525,21 @@ abd_get_offset_impl(abd_t *abd, abd_t *sabd, size_t off, size_t size) */ abd->abd_flags |= ABD_FLAG_LINEAR; + /* + * User pages from Direct I/O requests may be in a single page + * (ABD_FLAG_LINEAR_PAGE), and we must make sure to still flag + * that here for abd. This is required because we have to be + * careful when borrowing the buffer from the ABD because we + * can not place user pages under write protection on Linux. + * See the comments in abd_os.c for abd_borrow_buf(), + * abd_borrow_buf_copy(), abd_return_buf() and + * abd_return_buf_copy(). + */ + if (abd_is_from_pages(sabd)) { + abd->abd_flags |= ABD_FLAG_FROM_PAGES | + ABD_FLAG_LINEAR_PAGE; + } + ABD_LINEAR_BUF(abd) = (char *)ABD_LINEAR_BUF(sabd) + off; } else if (abd_is_gang(sabd)) { size_t left = size; @@ -648,70 +668,6 @@ abd_to_buf(abd_t *abd) return (ABD_LINEAR_BUF(abd)); } -/* - * Borrow a raw buffer from an ABD without copying the contents of the ABD - * into the buffer. If the ABD is scattered, this will allocate a raw buffer - * whose contents are undefined. To copy over the existing data in the ABD, use - * abd_borrow_buf_copy() instead. - */ -void * -abd_borrow_buf(abd_t *abd, size_t n) -{ - void *buf; - abd_verify(abd); - ASSERT3U(abd->abd_size, >=, n); - if (abd_is_linear(abd)) { - buf = abd_to_buf(abd); - } else { - buf = zio_buf_alloc(n); - } -#ifdef ZFS_DEBUG - (void) zfs_refcount_add_many(&abd->abd_children, n, buf); -#endif - return (buf); -} - -void * -abd_borrow_buf_copy(abd_t *abd, size_t n) -{ - void *buf = abd_borrow_buf(abd, n); - if (!abd_is_linear(abd)) { - abd_copy_to_buf(buf, abd, n); - } - return (buf); -} - -/* - * Return a borrowed raw buffer to an ABD. If the ABD is scattered, this will - * not change the contents of the ABD and will ASSERT that you didn't modify - * the buffer since it was borrowed. If you want any changes you made to buf to - * be copied back to abd, use abd_return_buf_copy() instead. - */ -void -abd_return_buf(abd_t *abd, void *buf, size_t n) -{ - abd_verify(abd); - ASSERT3U(abd->abd_size, >=, n); -#ifdef ZFS_DEBUG - (void) zfs_refcount_remove_many(&abd->abd_children, n, buf); -#endif - if (abd_is_linear(abd)) { - ASSERT3P(buf, ==, abd_to_buf(abd)); - } else { - ASSERT0(abd_cmp_buf(abd, buf, n)); - zio_buf_free(buf, n); - } -} - -void -abd_return_buf_copy(abd_t *abd, void *buf, size_t n) -{ - if (!abd_is_linear(abd)) { - abd_copy_from_buf(abd, buf, n); - } - abd_return_buf(abd, buf, n); -} - void abd_release_ownership_of_buf(abd_t *abd) { |