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[73.93.5.123]) by smtp.gmail.com with ESMTPSA id c22sm175770pfc.12.2021.02.16.17.08.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Feb 2021 17:08:39 -0800 (PST) Sender: Joe Stringer From: Joe Stringer To: bpf@vger.kernel.org Cc: Joe Stringer , netdev@vger.kernel.org, daniel@iogearbox.net, ast@kernel.org, mtk.manpages@gmail.com, Quentin Monnet , Brian Vazquez , Yonghong Song Subject: [PATCH bpf-next 08/17] bpf: Document BPF_MAP_*_BATCH syscall commands Date: Tue, 16 Feb 2021 17:08:12 -0800 Message-Id: <20210217010821.1810741-9-joe@wand.net.nz> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210217010821.1810741-1-joe@wand.net.nz> References: <20210217010821.1810741-1-joe@wand.net.nz> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Joe Stringer Based roughly on the following commits: * Commit cb4d03ab499d ("bpf: Add generic support for lookup batch op") * Commit 057996380a42 ("bpf: Add batch ops to all htab bpf map") * Commit aa2e93b8e58e ("bpf: Add generic support for update and delete batch ops") Reviewed-by: Quentin Monnet Signed-off-by: Joe Stringer --- CC: Brian Vazquez CC: Yonghong Song @Yonghong, would you mind double-checking whether the text is accurate for the case where BPF_MAP_LOOKUP_AND_DELETE_BATCH returns -EFAULT? --- include/uapi/linux/bpf.h | 114 +++++++++++++++++++++++++++++++++++++-- 1 file changed, 111 insertions(+), 3 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index a07cecfd2148..893803f69a64 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -550,13 +550,55 @@ union bpf_iter_link_info { * Description * Iterate and fetch multiple elements in a map. * + * Two opaque values are used to manage batch operations, + * *in_batch* and *out_batch*. Initially, *in_batch* must be set + * to NULL to begin the batched operation. After each subsequent + * **BPF_MAP_LOOKUP_BATCH**, the caller should pass the resultant + * *out_batch* as the *in_batch* for the next operation to + * continue iteration from the current point. + * + * The *keys* and *values* are output parameters which must point + * to memory large enough to hold *count* items based on the key + * and value size of the map *map_fd*. The *keys* buffer must be + * of *key_size* * *count*. The *values* buffer must be of + * *value_size* * *count*. + * + * The *elem_flags* argument may be specified as one of the + * following: + * + * **BPF_F_LOCK** + * Look up the value of a spin-locked map without + * returning the lock. This must be specified if the + * elements contain a spinlock. + * + * On success, *count* elements from the map are copied into the + * user buffer, with the keys copied into *keys* and the values + * copied into the corresponding indices in *values*. + * + * If an error is returned and *errno* is not **EFAULT**, *count* + * is set to the number of successfully processed elements. + * * Return * Returns zero on success. On error, -1 is returned and *errno* * is set appropriately. * + * May set *errno* to **ENOSPC** to indicate that *keys* or + * *values* is too small to dump an entire bucket during + * iteration of a hash-based map type. + * * BPF_MAP_LOOKUP_AND_DELETE_BATCH * Description - * Iterate and delete multiple elements in a map. + * Iterate and delete all elements in a map. + * + * This operation has the same behavior as + * **BPF_MAP_LOOKUP_BATCH** with two exceptions: + * + * * Every element that is successfully returned is also deleted + * from the map. This is at least *count* elements. Note that + * *count* is both an input and an output parameter. + * * Upon returning with *errno* set to **EFAULT**, up to + * *count* elements may be deleted without returning the keys + * and values of the deleted elements. * * Return * Returns zero on success. On error, -1 is returned and *errno* @@ -564,15 +606,81 @@ union bpf_iter_link_info { * * BPF_MAP_UPDATE_BATCH * Description - * Iterate and update multiple elements in a map. + * Update multiple elements in a map by *key*. + * + * The *keys* and *values* are input parameters which must point + * to memory large enough to hold *count* items based on the key + * and value size of the map *map_fd*. The *keys* buffer must be + * of *key_size* * *count*. The *values* buffer must be of + * *value_size* * *count*. + * + * Each element specified in *keys* is sequentially updated to the + * value in the corresponding index in *values*. The *in_batch* + * and *out_batch* parameters are ignored and should be zeroed. + * + * The *elem_flags* argument should be specified as one of the + * following: + * + * **BPF_ANY** + * Create new elements or update a existing elements. + * **BPF_NOEXIST** + * Create new elements only if they do not exist. + * **BPF_EXIST** + * Update existing elements. + * **BPF_F_LOCK** + * Update spin_lock-ed map elements. This must be + * specified if the map value contains a spinlock. + * + * On success, *count* elements from the map are updated. + * + * If an error is returned and *errno* is not **EFAULT**, *count* + * is set to the number of successfully processed elements. * * Return * Returns zero on success. On error, -1 is returned and *errno* * is set appropriately. * + * May set *errno* to **EINVAL**, **EPERM**, **ENOMEM**, or + * **E2BIG**. **E2BIG** indicates that the number of elements in + * the map reached the *max_entries* limit specified at map + * creation time. + * + * May set *errno* to one of the following error codes under + * specific circumstances: + * + * **EEXIST** + * If *flags* specifies **BPF_NOEXIST** and the element + * with *key* already exists in the map. + * **ENOENT** + * If *flags* specifies **BPF_EXIST** and the element with + * *key* does not exist in the map. + * * BPF_MAP_DELETE_BATCH * Description - * Iterate and delete multiple elements in a map. + * Delete multiple elements in a map by *key*. + * + * The *keys* parameter is an input parameter which must point + * to memory large enough to hold *count* items based on the key + * size of the map *map_fd*, that is, *key_size* * *count*. + * + * Each element specified in *keys* is sequentially deleted. The + * *in_batch*, *out_batch*, and *values* parameters are ignored + * and should be zeroed. + * + * The *elem_flags* argument may be specified as one of the + * following: + * + * **BPF_F_LOCK** + * Look up the value of a spin-locked map without + * returning the lock. This must be specified if the + * elements contain a spinlock. + * + * On success, *count* elements from the map are updated. + * + * If an error is returned and *errno* is not **EFAULT**, *count* + * is set to the number of successfully processed elements. If + * *errno* is **EFAULT**, up to *count* elements may be been + * deleted. * * Return * Returns zero on success. On error, -1 is returned and *errno*