IB/core: Add debugging prints to ib_uverbs_write

These debug prints should help anyone attempting to understand
why -EINVAL was returned for a command.

Signed-off-by: Haggai Eran <haggaie@mellanox.com>
(Ported from Mellanox OFED 2.4)

Signed-off-by: Mukesh Kacker <mukesh.kacker@oracle.com>

diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index fa93c4e08d885528ef1ea4e98dca8f46aa5441fe..6be3f0faa17a223f3fee72382a46ecac842f6184 100644 (file)
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -608,10 +608,12 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
        struct ib_uverbs_cmd_hdr hdr;
        __u32 flags;
 
-       if (count < sizeof hdr)
+       if (count < sizeof(hdr)) {
+               pr_debug("ib_uverbs_write: header too short\n");
                return -EINVAL;
+       }
 
-       if (copy_from_user(&hdr, buf, sizeof hdr))
+       if (copy_from_user(&hdr, buf, sizeof(hdr)))
                return -EFAULT;
 
        flags = (hdr.command &
@@ -627,18 +629,26 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
                command = hdr.command & IB_USER_VERBS_CMD_COMMAND_MASK;
 
                if (command >= ARRAY_SIZE(uverbs_cmd_table) ||
-                   !uverbs_cmd_table[command])
+                   !uverbs_cmd_table[command]) {
+                       pr_debug("ib_uverbs_write: unexpected command\n");
                        return -EINVAL;
+               }
 
                if (!file->ucontext &&
-                   command != IB_USER_VERBS_CMD_GET_CONTEXT)
+                   command != IB_USER_VERBS_CMD_GET_CONTEXT) {
+                       pr_debug("ib_uverbs_write: invalid context\n");
                        return -EINVAL;
+               }
 
-               if (!(file->device->ib_dev->uverbs_cmd_mask & (1ull << command)))
+               if (!(file->device->ib_dev->uverbs_cmd_mask & (1ull << command))) {
+                       pr_debug("ib_uverbs_write: command not support by the device\n");
                        return -ENOSYS;
+               }
 
-               if (hdr.in_words * 4 != count)
+               if (hdr.in_words * 4 != count) {
+                       pr_debug("ib_uverbs_write: header input length doesn't match written length\n");
                        return -EINVAL;
+               }
 
                return uverbs_cmd_table[command](file,
                                                 buf + sizeof(hdr),
@@ -655,23 +665,33 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
                size_t written_count = count;
 
                if (hdr.command & ~(__u32)(IB_USER_VERBS_CMD_FLAGS_MASK |
-                                          IB_USER_VERBS_CMD_COMMAND_MASK))
+                                          IB_USER_VERBS_CMD_COMMAND_MASK)) {
+                       pr_debug("ib_uverbs_write: extended command invalid opcode\n");
                        return -EINVAL;
+               }
 
                command = hdr.command & IB_USER_VERBS_CMD_COMMAND_MASK;
 
                if (command >= ARRAY_SIZE(uverbs_ex_cmd_table) ||
-                   !uverbs_ex_cmd_table[command])
+                   !uverbs_ex_cmd_table[command]) {
+                       pr_debug("ib_uverbs_write: invalid extended command\n");
                        return -ENOSYS;
+               }
 
-               if (!file->ucontext)
+               if (!file->ucontext) {
+                       pr_debug("ib_uverbs_write: invalid context in extended command\n");
                        return -EINVAL;
+               }
 
-               if (!(file->device->ib_dev->uverbs_ex_cmd_mask & (1ull << command)))
+               if (!(file->device->ib_dev->uverbs_ex_cmd_mask & (1ull << command))) {
+                       pr_debug("ib_uverbs_write: extended command not supported by driver\n");
                        return -ENOSYS;
+               }
 
-               if (count < (sizeof(hdr) + sizeof(ex_hdr)))
+               if (count < (sizeof(hdr) + sizeof(ex_hdr))) {
+                       pr_debug("ib_uverbs_write: ex header input length doesn't match written length\n");
                        return -EINVAL;
+               }
 
                if (copy_from_user(&ex_hdr, buf + sizeof(hdr), sizeof(ex_hdr)))
                        return -EFAULT;
@@ -679,23 +699,29 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
                count -= sizeof(hdr) + sizeof(ex_hdr);
                buf += sizeof(hdr) + sizeof(ex_hdr);
 
-               if ((hdr.in_words + ex_hdr.provider_in_words) * 8 != count)
+               if ((hdr.in_words + ex_hdr.provider_in_words) * 8 != count) {
+                       pr_debug("ib_uverbs_write: extended command doesn't match written length\n");
                        return -EINVAL;
+               }
 
                if (ex_hdr.cmd_hdr_reserved)
                        return -EINVAL;
 
                if (ex_hdr.response) {
-                       if (!hdr.out_words && !ex_hdr.provider_out_words)
+                       if (!hdr.out_words && !ex_hdr.provider_out_words) {
+                               pr_debug("ib_uverbs_write: got response pointer to a zero length buffer\n");
                                return -EINVAL;
+                       }
 
                        if (!access_ok(VERIFY_WRITE,
                                       (void __user *) (unsigned long) ex_hdr.response,
                                       (hdr.out_words + ex_hdr.provider_out_words) * 8))
                                return -EFAULT;
                } else {
-                       if (hdr.out_words || ex_hdr.provider_out_words)
+                       if (hdr.out_words || ex_hdr.provider_out_words) {
+                               pr_debug("ib_uverbs_write: got NULL response pointer but non-zero output length\n");
                                return -EINVAL;
+                       }
                }
 
                INIT_UDATA_BUF_OR_NULL(&ucore, buf, (unsigned long) ex_hdr.response,