Re: [PATCH v3] vdpa/sfc: make MCDI memzone name unique

[Maxime Coquelin]

On 2/14/22 11:51, abhimanyu.sa...@xilinx.com wrote:
From: Abhimanyu Saini <asa...@xilinx.com>

Buffer for MCDI channel is allocated using rte_memzone_reserve_aligned
with zone name 'mcdi'. Since multiple MCDI channels are needed to
support multiple VF(s) and rte_memzone_reserve_aligned expects unique
zone names, append PCI address to zone name to make it unique.

Signed-off-by: Abhimanyu Saini <asa...@xilinx.com>
---
v2:
   - Formatting changes
v3:
   - Formatting changes

  drivers/vdpa/sfc/sfc_vdpa_hw.c | 15 ++++++++++++---
  1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/vdpa/sfc/sfc_vdpa_hw.c b/drivers/vdpa/sfc/sfc_vdpa_hw.c
index fd1fee7..a7018b1 100644
--- a/drivers/vdpa/sfc/sfc_vdpa_hw.c
+++ b/drivers/vdpa/sfc/sfc_vdpa_hw.c
@@ -25,21 +25,30 @@
  {
        uint64_t mcdi_iova;
        size_t mcdi_buff_size;
+       char mz_name[RTE_MEMZONE_NAMESIZE];
        const struct rte_memzone *mz = NULL;
        int numa_node = sva->pdev->device.numa_node;
        int ret;
  
  	mcdi_buff_size = RTE_ALIGN_CEIL(len, PAGE_SIZE);
+       ret = snprintf(mz_name, RTE_MEMZONE_NAMESIZE, "%s_%s",
+                      sva->pdev->name, name);
+       if (ret < 0 || ret >= RTE_MEMZONE_NAMESIZE) {

From the man page:
"
The functions snprintf() and vsnprintf() do not write more than size 
bytes (including the terminating null byte ('\0')).
"

you might want to pass RTE_MEMZONE_NAMESIZE - 1 as size arg to snprintf,
so you can just check ret >= 0?

+               sfc_vdpa_err(sva, "%s_%s too long to fit in mz_name",
+                            sva->pdev->name, name);
+               return -EINVAL;
+       }
  
-	sfc_vdpa_log_init(sva, "name=%s, len=%zu", name, len);
+       sfc_vdpa_log_init(sva, "name=%s, len=%zu", mz_name, len);
  
-	mz = rte_memzone_reserve_aligned(name, mcdi_buff_size,
+       mz = rte_memzone_reserve_aligned(mz_name, mcdi_buff_size,
                                         numa_node,
                                         RTE_MEMZONE_IOVA_CONTIG,
                                         PAGE_SIZE);
        if (mz == NULL) {
                sfc_vdpa_err(sva, "cannot reserve memory for %s: len=%#x: %s",
-                            name, (unsigned int)len, rte_strerror(rte_errno));
+                            mz_name, (unsigned int)len,
+                            rte_strerror(rte_errno));
                return -ENOMEM;
        }