[PATCH v2 4/7] riscv: Simplify text patching loops

From: Samuel Holland
Date: Wed Mar 27 2024 - 12:12:11 EST


This reduces the number of variables and makes the code easier to parse.

Signed-off-by: Samuel Holland <samuel.holland@xxxxxxxxxx>
---

Changes in v2:
- Further simplify patch_insn_set()/patch_insn_write() loop conditions
- Use min() instead of min_t() since both sides are unsigned long

arch/riscv/kernel/patch.c | 37 +++++++++++++++++++++----------------
1 file changed, 21 insertions(+), 16 deletions(-)

diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c
index 9a1bce1adf5a..0d1700d1934c 100644
--- a/arch/riscv/kernel/patch.c
+++ b/arch/riscv/kernel/patch.c
@@ -155,22 +155,24 @@ NOKPROBE_SYMBOL(__patch_insn_write);

static int patch_insn_set(void *addr, u8 c, size_t len)
{
- size_t patched = 0;
size_t size;
- int ret = 0;
+ int ret;

/*
* __patch_insn_set() can only work on 2 pages at a time so call it in a
* loop with len <= 2 * PAGE_SIZE.
*/
- while (patched < len && !ret) {
- size = min_t(size_t, PAGE_SIZE * 2 - offset_in_page(addr + patched), len - patched);
- ret = __patch_insn_set(addr + patched, c, size);
-
- patched += size;
+ while (len) {
+ size = min(len, PAGE_SIZE * 2 - offset_in_page(addr));
+ ret = __patch_insn_set(addr, c, size);
+ if (ret)
+ return ret;
+
+ addr += size;
+ len -= size;
}

- return ret;
+ return 0;
}
NOKPROBE_SYMBOL(patch_insn_set);

@@ -190,22 +192,25 @@ NOKPROBE_SYMBOL(patch_text_set_nosync);

int patch_insn_write(void *addr, const void *insn, size_t len)
{
- size_t patched = 0;
size_t size;
- int ret = 0;
+ int ret;

/*
* Copy the instructions to the destination address, two pages at a time
* because __patch_insn_write() can only handle len <= 2 * PAGE_SIZE.
*/
- while (patched < len && !ret) {
- size = min_t(size_t, PAGE_SIZE * 2 - offset_in_page(addr + patched), len - patched);
- ret = __patch_insn_write(addr + patched, insn + patched, size);
-
- patched += size;
+ while (len) {
+ size = min(len, PAGE_SIZE * 2 - offset_in_page(addr));
+ ret = __patch_insn_write(addr, insn, size);
+ if (ret)
+ return ret;
+
+ addr += size;
+ insn += size;
+ len -= size;
}

- return ret;
+ return 0;
}
NOKPROBE_SYMBOL(patch_insn_write);

--
2.43.1