On Mon, Sep 11, 2023 at 04:48:37PM +0200, Philipp Stanner wrote: > Calling functions that wrap __xa_alloc() or __xa_alloc_cyclic() without > the xarray previously having been initialized with the flag > XA_FLAGS_ALLOC being set in xa_init_flags() results in undefined > behavior. > > Document the necessity of setting this flag in all docstrings of > functions that wrap said two functions. > > Signed-off-by: Philipp Stanner <pstanner@xxxxxxxxxx> > --- > I used the time available until we can get this merged to create a > version-3, improving a few things. Umm, too late, v2 went upstream last week during the merge window. Do you still want to change the wording? > Changes since v2: > - Phrase the comment differently: say "requires [...] an xarray [...]" > instead of "must be operated on". > - Improve the commit message and use the canonical format: a) describe > the problem, b) name the solution in imperative form. > > Regards, > P. > --- > include/linux/xarray.h | 18 ++++++++++++++++++ > lib/xarray.c | 6 ++++++ > 2 files changed, 24 insertions(+) > > diff --git a/include/linux/xarray.h b/include/linux/xarray.h > index 741703b45f61..746a17b64aa6 100644 > --- a/include/linux/xarray.h > +++ b/include/linux/xarray.h > @@ -856,6 +856,9 @@ static inline int __must_check xa_insert_irq(struct xarray *xa, > * stores the index into the @id pointer, then stores the entry at > * that index. A concurrent lookup will not see an uninitialised @id. > * > + * Requires the xarray to be initialized with flag XA_FLAGS_ALLOC set > + * in xa_init_flags(). > + * > * Context: Any context. Takes and releases the xa_lock. May sleep if > * the @gfp flags permit. > * Return: 0 on success, -ENOMEM if memory could not be allocated or > @@ -886,6 +889,9 @@ static inline __must_check int xa_alloc(struct xarray *xa, u32 *id, > * stores the index into the @id pointer, then stores the entry at > * that index. A concurrent lookup will not see an uninitialised @id. > * > + * Requires the xarray to be initialized with flag XA_FLAGS_ALLOC set > + * in xa_init_flags(). > + * > * Context: Any context. Takes and releases the xa_lock while > * disabling softirqs. May sleep if the @gfp flags permit. > * Return: 0 on success, -ENOMEM if memory could not be allocated or > @@ -916,6 +922,9 @@ static inline int __must_check xa_alloc_bh(struct xarray *xa, u32 *id, > * stores the index into the @id pointer, then stores the entry at > * that index. A concurrent lookup will not see an uninitialised @id. > * > + * Requires the xarray to be initialized with flag XA_FLAGS_ALLOC set > + * in xa_init_flags(). > + * > * Context: Process context. Takes and releases the xa_lock while > * disabling interrupts. May sleep if the @gfp flags permit. > * Return: 0 on success, -ENOMEM if memory could not be allocated or > @@ -949,6 +958,9 @@ static inline int __must_check xa_alloc_irq(struct xarray *xa, u32 *id, > * The search for an empty entry will start at @next and will wrap > * around if necessary. > * > + * Requires the xarray to be initialized with flag XA_FLAGS_ALLOC set > + * in xa_init_flags(). > + * > * Context: Any context. Takes and releases the xa_lock. May sleep if > * the @gfp flags permit. > * Return: 0 if the allocation succeeded without wrapping. 1 if the > @@ -983,6 +995,9 @@ static inline int xa_alloc_cyclic(struct xarray *xa, u32 *id, void *entry, > * The search for an empty entry will start at @next and will wrap > * around if necessary. > * > + * Requires the xarray to be initialized with flag XA_FLAGS_ALLOC set > + * in xa_init_flags(). > + * > * Context: Any context. Takes and releases the xa_lock while > * disabling softirqs. May sleep if the @gfp flags permit. > * Return: 0 if the allocation succeeded without wrapping. 1 if the > @@ -1017,6 +1032,9 @@ static inline int xa_alloc_cyclic_bh(struct xarray *xa, u32 *id, void *entry, > * The search for an empty entry will start at @next and will wrap > * around if necessary. > * > + * Requires the xarray to be initialized with flag XA_FLAGS_ALLOC set > + * in xa_init_flags(). > + * > * Context: Process context. Takes and releases the xa_lock while > * disabling interrupts. May sleep if the @gfp flags permit. > * Return: 0 if the allocation succeeded without wrapping. 1 if the > diff --git a/lib/xarray.c b/lib/xarray.c > index 2071a3718f4e..2b07c332d26b 100644 > --- a/lib/xarray.c > +++ b/lib/xarray.c > @@ -1802,6 +1802,9 @@ EXPORT_SYMBOL(xa_get_order); > * stores the index into the @id pointer, then stores the entry at > * that index. A concurrent lookup will not see an uninitialised @id. > * > + * Requires the xarray to be initialized with flag XA_FLAGS_ALLOC set > + * in xa_init_flags(). > + * > * Context: Any context. Expects xa_lock to be held on entry. May > * release and reacquire xa_lock if @gfp flags permit. > * Return: 0 on success, -ENOMEM if memory could not be allocated or > @@ -1850,6 +1853,9 @@ EXPORT_SYMBOL(__xa_alloc); > * The search for an empty entry will start at @next and will wrap > * around if necessary. > * > + * Requires the xarray to be initialized with flag XA_FLAGS_ALLOC set > + * in xa_init_flags(). > + * > * Context: Any context. Expects xa_lock to be held on entry. May > * release and reacquire xa_lock if @gfp flags permit. > * Return: 0 if the allocation succeeded without wrapping. 1 if the > -- > 2.41.0 >
