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| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2019-11-08 06:49:11 +0300 |
|---|---|---|
| committer | Matthew Wilcox (Oracle) <willy@infradead.org> | 2019-11-09 07:48:40 +0300 |
| commit | 82a22311b7a68a78709699dc8c098953b70e4fd2 (patch) | |
| tree | 60accb87ad1602692b42931ede847c3d1239478b | |
| parent | 0058b0a506e40d9a2c62015fe92eb64a44d78cd9 (diff) | |
| download | linux-82a22311b7a68a78709699dc8c098953b70e4fd2.tar.xz | |
XArray: Fix xas_pause at ULONG_MAX
If we were unlucky enough to call xas_pause() when the index was at
ULONG_MAX (or a multi-slot entry which ends at ULONG_MAX), we would
wrap the index back around to 0 and restart the iteration from the
beginning. Use the XAS_BOUNDS state to indicate that we should just
stop the iteration.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
| -rw-r--r-- | lib/test_xarray.c | 22 | ||||
| -rw-r--r-- | lib/xarray.c | 8 |
2 files changed, 27 insertions, 3 deletions
diff --git a/lib/test_xarray.c b/lib/test_xarray.c index 7df4f7f395bf..c477f22a95cd 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -1132,6 +1132,27 @@ static noinline void check_move_tiny(struct xarray *xa) XA_BUG_ON(xa, !xa_empty(xa)); } +static noinline void check_move_max(struct xarray *xa) +{ + XA_STATE(xas, xa, 0); + + xa_store_index(xa, ULONG_MAX, GFP_KERNEL); + rcu_read_lock(); + XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != xa_mk_index(ULONG_MAX)); + XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != NULL); + rcu_read_unlock(); + + xas_set(&xas, 0); + rcu_read_lock(); + XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != xa_mk_index(ULONG_MAX)); + xas_pause(&xas); + XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != NULL); + rcu_read_unlock(); + + xa_erase_index(xa, ULONG_MAX); + XA_BUG_ON(xa, !xa_empty(xa)); +} + static noinline void check_move_small(struct xarray *xa, unsigned long idx) { XA_STATE(xas, xa, 0); @@ -1240,6 +1261,7 @@ static noinline void check_move(struct xarray *xa) xa_destroy(xa); check_move_tiny(xa); + check_move_max(xa); for (i = 0; i < 16; i++) check_move_small(xa, 1UL << i); diff --git a/lib/xarray.c b/lib/xarray.c index 1237c213f52b..bfaaa2c1f3fe 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -967,6 +967,7 @@ void xas_pause(struct xa_state *xas) if (xas_invalid(xas)) return; + xas->xa_node = XAS_RESTART; if (node) { unsigned int offset = xas->xa_offset; while (++offset < XA_CHUNK_SIZE) { @@ -974,10 +975,11 @@ void xas_pause(struct xa_state *xas) break; } xas->xa_index += (offset - xas->xa_offset) << node->shift; + if (xas->xa_index == 0) + xas->xa_node = XAS_BOUNDS; } else { xas->xa_index++; } - xas->xa_node = XAS_RESTART; } EXPORT_SYMBOL_GPL(xas_pause); @@ -1079,13 +1081,13 @@ void *xas_find(struct xa_state *xas, unsigned long max) { void *entry; - if (xas_error(xas)) + if (xas_error(xas) || xas->xa_node == XAS_BOUNDS) return NULL; if (!xas->xa_node) { xas->xa_index = 1; return set_bounds(xas); - } else if (xas_top(xas->xa_node)) { + } else if (xas->xa_node == XAS_RESTART) { entry = xas_load(xas); if (entry || xas_not_node(xas->xa_node)) return entry; |