5.4-stable review patch. If anyone has any objections, please let me know.
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From: Ovidiu Panait ovidiu.panait.oss@gmail.com
commit 82a051e2553b9e297cba82a975d9c538b882c79e upstream.
Flush stale data from the RX FIFO in case of errors, to avoid reading old data when new packets arrive.
Commit c6e8d85fafa7 ("staging: axis-fifo: Remove hardware resets for user errors") removed full FIFO resets from the read error paths, which fixed potential TX data losses, but introduced this RX issue.
Fixes: c6e8d85fafa7 ("staging: axis-fifo: Remove hardware resets for user errors") Cc: stable@vger.kernel.org Signed-off-by: Ovidiu Panait ovidiu.panait.oss@gmail.com Link: https://lore.kernel.org/r/20250912101322.1282507-2-ovidiu.panait.oss@gmail.c... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/staging/axis-fifo/axis-fifo.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-)
--- a/drivers/staging/axis-fifo/axis-fifo.c +++ b/drivers/staging/axis-fifo/axis-fifo.c @@ -400,6 +400,7 @@ static ssize_t axis_fifo_read(struct fil }
bytes_available = ioread32(fifo->base_addr + XLLF_RLR_OFFSET); + words_available = bytes_available / sizeof(u32); if (!bytes_available) { dev_err(fifo->dt_device, "received a packet of length 0\n"); ret = -EIO; @@ -410,7 +411,7 @@ static ssize_t axis_fifo_read(struct fil dev_err(fifo->dt_device, "user read buffer too small (available bytes=%zu user buffer bytes=%zu)\n", bytes_available, len); ret = -EINVAL; - goto end_unlock; + goto err_flush_rx; }
if (bytes_available % sizeof(u32)) { @@ -419,11 +420,9 @@ static ssize_t axis_fifo_read(struct fil */ dev_err(fifo->dt_device, "received a packet that isn't word-aligned\n"); ret = -EIO; - goto end_unlock; + goto err_flush_rx; }
- words_available = bytes_available / sizeof(u32); - /* read data into an intermediate buffer, copying the contents * to userspace when the buffer is full */ @@ -435,18 +434,23 @@ static ssize_t axis_fifo_read(struct fil tmp_buf[i] = ioread32(fifo->base_addr + XLLF_RDFD_OFFSET); } + words_available -= copy;
if (copy_to_user(buf + copied * sizeof(u32), tmp_buf, copy * sizeof(u32))) { ret = -EFAULT; - goto end_unlock; + goto err_flush_rx; }
copied += copy; - words_available -= copy; } + mutex_unlock(&fifo->read_lock); + + return bytes_available;
- ret = bytes_available; +err_flush_rx: + while (words_available--) + ioread32(fifo->base_addr + XLLF_RDFD_OFFSET);
end_unlock: mutex_unlock(&fifo->read_lock);