9p: fix sparse warnings

Several sparse warnings were introduced by patches accepted during the merge
window which weren't caught. This patch fixes those warnings.

Signed-off-by: Eric Van Hensbergen <[e-mail]>

include/net/9p/client.h

···
 	struct list_head dlist;	/* list of all fids attached to a dentry */
 };
 
+int p9_client_version(struct p9_client *);
 struct p9_client *p9_client_create(const char *dev_name, char *options);
 void p9_client_destroy(struct p9_client *clnt);
 void p9_client_disconnect(struct p9_client *clnt);

net/9p/client.c

···
 
 			if (!c->reqs[row]) {
 				printk(KERN_ERR "Couldn't grow tag array\n");
+				spin_unlock_irqrestore(&c->lock, flags);
 				return ERR_PTR(-ENOMEM);
 			}
 			for (col = 0; col < P9_ROW_MAXTAG; col++) {

net/9p/protocol.c

···
 			}
 			break;
 		case 's':{
-				char **ptr = va_arg(ap, char **);
+				char **sptr = va_arg(ap, char **);
 				int16_t len;
 				int size;
 
···
 
 				size = MAX(len, 0);
 
-				*ptr = kmalloc(size + 1, GFP_KERNEL);
-				if (*ptr == NULL) {
+				*sptr = kmalloc(size + 1, GFP_KERNEL);
+				if (*sptr == NULL) {
 					errcode = -EFAULT;
 					break;
 				}
-				if (pdu_read(pdu, *ptr, size)) {
+				if (pdu_read(pdu, *sptr, size)) {
 					errcode = -EFAULT;
-					kfree(*ptr);
-					*ptr = NULL;
+					kfree(*sptr);
+					*sptr = NULL;
 				} else
-					(*ptr)[size] = 0;
+					(*sptr)[size] = 0;
 			}
 			break;
 		case 'Q':{
···
 			}
 			break;
 		case 's':{
-				const char *ptr = va_arg(ap, const char *);
+				const char *sptr = va_arg(ap, const char *);
 				int16_t len = 0;
-				if (ptr)
-					len = MIN(strlen(ptr), USHORT_MAX);
+				if (sptr)
+					len = MIN(strlen(sptr), USHORT_MAX);
 
 				errcode = p9pdu_writef(pdu, optional, "w", len);
-				if (!errcode && pdu_write(pdu, ptr, len))
+				if (!errcode && pdu_write(pdu, sptr, len))
 					errcode = -EFAULT;
 			}
 			break;
···
 		case 'U':{
 				int32_t count = va_arg(ap, int32_t);
 				const char __user *udata =
-						va_arg(ap, const void *);
+						va_arg(ap, const void __user *);
 				errcode =
 				    p9pdu_writef(pdu, optional, "d", count);
 				if (!errcode && pdu_write_u(pdu, udata, count))