[tip: x86/alternatives] x86/alternatives: Document 'smp_text_poke_single()'

[tip-bot2 for Ingo Molnar]

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID:     9647ce465265720509f80f21f0b36c00bb0c0d18
Gitweb:        https://git.kernel.org/tip/9647ce465265720509f80f21f0b36c00bb0c0d18
Author:        Ingo Molnar <mingo@xxxxxxxxxx>
AuthorDate:    Fri, 11 Apr 2025 07:40:49 +02:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Fri, 11 Apr 2025 11:01:34 +02:00

x86/alternatives: Document 'smp_text_poke_single()'

Extend the documentation to better describe its purpose.

Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: "H . Peter Anvin" <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20250411054105.2341982-38-mingo@xxxxxxxxxx
---
 arch/x86/kernel/alternative.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index f0bb215..a9726cc 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -2880,7 +2880,7 @@ void __ref smp_text_poke_batch_add(void *addr, const void *opcode, size_t len, c
 }
 
 /**
- * smp_text_poke_single() -- update instructions on live kernel on SMP
+ * smp_text_poke_single() -- update instruction on live kernel on SMP immediately
  * @addr:	address to patch
  * @opcode:	opcode of new instruction
  * @len:	length to copy
@@ -2888,7 +2888,8 @@ void __ref smp_text_poke_batch_add(void *addr, const void *opcode, size_t len, c
  *
  * Update a single instruction with the vector in the stack, avoiding
  * dynamically allocated memory. This function should be used when it is
- * not possible to allocate memory.
+ * not possible to allocate memory for a vector. The single instruction
+ * is patched in immediately.
  */
 void __ref smp_text_poke_single(void *addr, const void *opcode, size_t len, const void *emulate)
 {