Re: [PATCH v5 06/29] packet: Add packet_data()

On Thu, 17 Apr 2025 18:51:13 +0200 Laurent Vivier wrote:

packet_data() gets the data range from a packet descriptor from a given pool.

It uses iov_tail to return the packet memory.

Signed-off-by: Laurent Vivier --- packet.c | 41 +++++++++++++++++++++++++++++++++++++++++ packet.h | 5 +++++ 2 files changed, 46 insertions(+)

diff --git a/packet.c b/packet.c index 98ded4e27aae..675bccf4d787 100644 --- a/packet.c +++ b/packet.c @@ -190,6 +190,47 @@ void *packet_get_do(const struct pool *p, const size_t idx, return r; }

+/** + * packet_data_do() - Get data range from packet descriptor from given pool

All the code changes here make sense to me, but the name itself, packet_data_do(), is rather cryptic, in the sense that 'data' is not a verb. Was this supposed to be a temporary name to use before removing packet_get_do() later in the series?

+ * @p: Packet pool + * @idx: Index of packet descriptor in pool + * @data: IOV tail to store the address of the data (output) + * @func: For tracing: name of calling function, NULL means no trace() + * @line: For tracing: caller line of function call + * + * Return: true if @data contains valid data, false otherwise

I think it's not so much about "valid" data (how do we define data validity here?): we return false if the packet index is invalid. If there's something wrong with @data, we don't return at all.

+ */ +/* cppcheck-suppress unusedFunction */ +bool packet_data_do(const struct pool *p, size_t idx, + struct iov_tail *data, + const char *func, int line) +{ + size_t i; + + ASSERT_WITH_MSG(p->count <= p->size, + "Corrupt pool count: %zu, size: %zu, %s:%i", + p->count, p->size, func, line); + + if (idx >= p->count) { + debug("packet %zu from pool size: %zu, count: %zu, " + "%s:%i", idx, p->size, p->count, func, line); + return false; + } + + data->cnt = 1; + data->off = 0; + data->iov = &p->pkt[idx]; + + for (i = 0; i < data->cnt; i++) { + ASSERT_WITH_MSG(!packet_check_range(p, data->iov[i].iov_base, + data->iov[i].iov_len, + func, line), + "Corrupt packet pool, %s:%i", func, line);

I think "Corrupted" is a bit more common in computing, but I guess it's correct either way.

+ } + + return true; +} + /** * pool_flush() - Flush a packet pool * @p: Pointer to packet pool diff --git a/packet.h b/packet.h index af40b39b5251..062afb978124 100644 --- a/packet.h +++ b/packet.h @@ -39,6 +39,9 @@ void *packet_get_try_do(const struct pool *p, const size_t idx, void *packet_get_do(const struct pool *p, const size_t idx, size_t offset, size_t len, size_t *left, const char *func, int line); +bool packet_data_do(const struct pool *p, const size_t idx, + struct iov_tail *data, + const char *func, int line); bool pool_full(const struct pool *p); void pool_flush(struct pool *p);

@@ -49,6 +52,8 @@ void pool_flush(struct pool *p); packet_get_try_do(p, idx, offset, len, left, __func__, __LINE__) #define packet_get(p, idx, offset, len, left) \ packet_get_do(p, idx, offset, len, left, __func__, __LINE__) +#define packet_data(p, idx, data) \ + packet_data_do(p, idx, data, __func__, __LINE__)

#define PACKET_POOL_DECL(_name, _size, _buf) \ struct _name ## _t { \

-- Stefano