Adds a new line to the docstrings of functions wrapping __xa_alloc() and __xa_alloc_cyclic(), informing about the necessity of flag XA_FLAGS_ALLOC being set previously. The documentation so far says that functions wrapping __xa_alloc() and __xa_alloc_cyclic() are supposed to return either -ENOMEM or -EBUSY in case of an error. If the xarray has been initialized without the flag XA_FLAGS_ALLOC, however, they fail with a different, undocumented error code. As hinted at in Documentation/core-api/xarray.rst, wrappers around these functions should only be invoked when the flag has been set. The functions' documentation should reflect that as well. Signed-off-by: Philipp Stanner <pstanner@xxxxxxxxxx> --- Version 2 of the proposed documentation update. As Matthew requested, I added the sentence to all functions wrapping the above mentioned two core functions. Additionally, I added it to themselves, too, as these functions can also be called by the user directly. I also rephrased the commit message so that the implemented change is mentioned first. --- 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..cb571dfcf4b1 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. * + * Must only be operated on an xarray 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. * + * Must only be operated on an xarray 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. * + * Must only be operated on an xarray 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. * + * Must only be operated on an xarray 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. * + * Must only be operated on an xarray 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. * + * Must only be operated on an xarray 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..73b3f8b33a56 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. * + * Must only be operated on an xarray 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. * + * Must only be operated on an xarray 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
