In preparation to limit the scope of a list iterator to the list
traversal loop, use a dedicated pointer pointing to the location
where the element should be inserted [1].

Before, the code implicitly used the head when no element was found
when using &new->list. The new 'pos' variable is set to the list head
by default and overwritten if the list exits early, marking the
insertion point for list_add().

Link: 
https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=ehreask5sqxpwr9y7k9sa6cwx...@mail.gmail.com/
 [1]
Signed-off-by: Jakob Koschel <jakobkosc...@gmail.com>
---
 drivers/net/ethernet/sfc/rx_common.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/sfc/rx_common.c 
b/drivers/net/ethernet/sfc/rx_common.c
index fa8b9aacca11..74c056210e0b 100644
--- a/drivers/net/ethernet/sfc/rx_common.c
+++ b/drivers/net/ethernet/sfc/rx_common.c
@@ -560,14 +560,17 @@ struct efx_rss_context 
*efx_alloc_rss_context_entry(struct efx_nic *efx)
 {
        struct list_head *head = &efx->rss_context.list;
        struct efx_rss_context *ctx, *new;
+       struct list_head *pos = head;
        u32 id = 1; /* Don't use zero, that refers to the master RSS context */
 
        WARN_ON(!mutex_is_locked(&efx->rss_lock));
 
        /* Search for first gap in the numbering */
        list_for_each_entry(ctx, head, list) {
-               if (ctx->user_id != id)
+               if (ctx->user_id != id) {
+                       pos = &ctx->list;
                        break;
+               }
                id++;
                /* Check for wrap.  If this happens, we have nearly 2^32
                 * allocated RSS contexts, which seems unlikely.
@@ -585,7 +588,7 @@ struct efx_rss_context *efx_alloc_rss_context_entry(struct 
efx_nic *efx)
 
        /* Insert the new entry into the gap */
        new->user_id = id;
-       list_add_tail(&new->list, &ctx->list);
+       list_add_tail(&new->list, pos);
        return new;
 }
 
-- 
2.25.1

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