bcachefs: Kill page_state_cmpxchg

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/fs-io.c b/fs/bcachefs/fs-io.c
index bf03048252ec117818e33bcb44e1c6cba82d8978..be4184debd7a7c6bacd9bf696b129b3819a1b68f 100644 (file)
--- a/fs/bcachefs/fs-io.c
+++ b/fs/bcachefs/fs-io.c
@@ -501,7 +501,6 @@ static inline struct bch_io_opts io_opts(struct bch_fs *c, struct bch_inode_info
 /* stored in page->private: */
 
 struct bch_page_state {
-union { struct {
        /* existing data: */
        unsigned                sectors:PAGE_SECTOR_SHIFT + 1;
 
@@ -519,28 +518,8 @@ union { struct {
         * Uncompressed size, not compressed size:
         */
        unsigned                dirty_sectors:PAGE_SECTOR_SHIFT + 1;
-};
-       /* for cmpxchg: */
-       unsigned long           v;
-};
 };
 
-#define page_state_cmpxchg(_ptr, _new, _expr)                          \
-({                                                                     \
-       unsigned long _v = READ_ONCE((_ptr)->v);                        \
-       struct bch_page_state _old;                                     \
-                                                                       \
-       do {                                                            \
-               _old.v = _new.v = _v;                                   \
-               _expr;                                                  \
-                                                                       \
-               EBUG_ON(_new.sectors + _new.dirty_sectors > PAGE_SECTORS);\
-       } while (_old.v != _new.v &&                                    \
-                (_v = cmpxchg(&(_ptr)->v, _old.v, _new.v)) != _old.v); \
-                                                                       \
-       _old;                                                           \
-})
-
 static inline struct bch_page_state *page_state(struct page *page)
 {
        struct bch_page_state *s = (void *) &page->private;
@@ -554,35 +533,22 @@ static inline struct bch_page_state *page_state(struct page *page)
        return s;
 }
 
-static inline unsigned page_res_sectors(struct bch_page_state s)
-{
-
-       return s.replicas_reserved * PAGE_SECTORS;
-}
-
-static void __bch2_put_page_reservation(struct bch_fs *c, struct bch_inode_info *inode,
-                                       struct bch_page_state s)
-{
-       struct disk_reservation res = { .sectors = page_res_sectors(s) };
-       struct quota_res quota_res = { .sectors = s.quota_reserved ? PAGE_SECTORS : 0 };
-
-       bch2_quota_reservation_put(c, inode, &quota_res);
-       bch2_disk_reservation_put(c, &res);
-}
-
 static void bch2_put_page_reservation(struct bch_fs *c, struct bch_inode_info *inode,
                                      struct page *page)
 {
-       struct bch_page_state s;
-
-       EBUG_ON(!PageLocked(page));
+       struct bch_page_state *s = page_state(page);
+       struct disk_reservation disk_res = {
+               .sectors = s->replicas_reserved * PAGE_SECTORS
+       };
+       struct quota_res quota_res = {
+               .sectors = s->quota_reserved ? PAGE_SECTORS : 0
+       };
 
-       s = page_state_cmpxchg(page_state(page), s, {
-               s.replicas_reserved     = 0;
-               s.quota_reserved        = 0;
-       });
+       s->replicas_reserved    = 0;
+       s->quota_reserved       = 0;
 
-       __bch2_put_page_reservation(c, inode, s);
+       bch2_quota_reservation_put(c, inode, &quota_res);
+       bch2_disk_reservation_put(c, &disk_res);
 }
 
 static inline unsigned inode_nr_replicas(struct bch_fs *c, struct bch_inode_info *inode)
@@ -596,8 +562,7 @@ static inline unsigned inode_nr_replicas(struct bch_fs *c, struct bch_inode_info
 static int bch2_get_page_reservation(struct bch_fs *c, struct bch_inode_info *inode,
                                     struct page *page, bool check_enospc)
 {
-       struct bch_page_state *s = page_state(page), new;
-
+       struct bch_page_state *s = page_state(page);
        unsigned nr_replicas = inode_nr_replicas(c, inode);
        struct disk_reservation disk_res;
        struct quota_res quota_res = { 0 };
@@ -612,11 +577,7 @@ static int bch2_get_page_reservation(struct bch_fs *c, struct bch_inode_info *in
                if (unlikely(ret))
                        return ret;
 
-               page_state_cmpxchg(s, new, ({
-                       BUG_ON(new.replicas_reserved +
-                              disk_res.nr_replicas != nr_replicas);
-                       new.replicas_reserved += disk_res.nr_replicas;
-               }));
+               s->replicas_reserved += disk_res.nr_replicas;
        }
 
        if (!s->quota_reserved &&
@@ -627,52 +588,48 @@ static int bch2_get_page_reservation(struct bch_fs *c, struct bch_inode_info *in
                if (unlikely(ret))
                        return ret;
 
-               page_state_cmpxchg(s, new, ({
-                       BUG_ON(new.quota_reserved);
-                       new.quota_reserved = 1;
-               }));
+               s->quota_reserved = 1;
        }
 
-       return ret;
+       return 0;
 }
 
 static void bch2_clear_page_bits(struct page *page)
 {
        struct bch_inode_info *inode = to_bch_ei(page->mapping->host);
        struct bch_fs *c = inode->v.i_sb->s_fs_info;
-       struct bch_page_state s;
+       struct bch_page_state *s;
 
        EBUG_ON(!PageLocked(page));
 
        if (!PagePrivate(page))
                return;
 
-       s.v = xchg(&page_state(page)->v, 0);
-       ClearPagePrivate(page);
+       s = page_state(page);
 
-       if (s.dirty_sectors)
-               i_sectors_acct(c, inode, NULL, -s.dirty_sectors);
+       if (s->dirty_sectors)
+               i_sectors_acct(c, inode, NULL, -((int) s->dirty_sectors));
+       bch2_put_page_reservation(c, inode, page);
 
-       __bch2_put_page_reservation(c, inode, s);
+       ClearPagePrivate(page);
+       set_page_private(page, 0);
 }
 
 static void __bch2_set_page_dirty(struct address_space *mapping, struct folio *folio)
 {
        struct bch_inode_info *inode = to_bch_ei(mapping->host);
        struct bch_fs *c = inode->v.i_sb->s_fs_info;
-       struct quota_res quota_res = { 0 };
-       struct bch_page_state old, new;
-
-       old = page_state_cmpxchg(page_state(&folio->page), new,
-               new.dirty_sectors = PAGE_SECTORS - new.sectors;
-               new.quota_reserved = 0;
-       );
+       struct bch_page_state *s = page_state(&folio->page);
+       struct quota_res quota_res = { s->quota_reserved * PAGE_SECTORS };
+       unsigned dirty_sectors = PAGE_SECTORS - s->sectors;
 
-       quota_res.sectors += old.quota_reserved * PAGE_SECTORS;
+       s->quota_reserved = 0;
 
-       if (old.dirty_sectors != new.dirty_sectors)
+       if (s->dirty_sectors != dirty_sectors)
                i_sectors_acct(c, inode, &quota_res,
-                              new.dirty_sectors - old.dirty_sectors);
+                              dirty_sectors - s->dirty_sectors);
+       s->dirty_sectors = dirty_sectors;
+
        bch2_quota_reservation_put(c, inode, &quota_res);
 }