Re: [PATCH] kexec: Delete an unnecessary comparison

[Joe Perches]

On Thu, 2020-08-13 at 20:45 +0800, Youling Tang wrote:
> Regardless of whether the ret value is zero or non-zero, the trajectory
> of the program execution is the same, so there is no need to compare.
> 
> Signed-off-by: Youling Tang <tangyoul...@loongson.cn>
> ---
>  kernel/kexec_file.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
> index 78c0837..3ad0ae2 100644
> --- a/kernel/kexec_file.c
> +++ b/kernel/kexec_file.c
> @@ -800,8 +800,6 @@ static int kexec_calculate_store_digests(struct kimage 
> *image)
>  
>               ret = kexec_purgatory_get_set_symbol(image, 
> "purgatory_sha256_digest",
>                                                    digest, 
> SHA256_DIGEST_SIZE, 0);
> -             if (ret)
> -                     goto out_free_digest;
>       }
>  
>  out_free_digest:

If you really want to change the function, then
you could change a couple of breaks to gotos,
remove multiple unnecessary tests, and unindent
a block of code too.

---
 kernel/kexec_file.c | 30 ++++++++++++------------------
 1 file changed, 12 insertions(+), 18 deletions(-)

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index ca40bef75a61..34a025e85887 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -763,7 +763,7 @@ static int kexec_calculate_store_digests(struct kimage 
*image)
                ret = crypto_shash_update(desc, ksegment->kbuf,
                                          ksegment->bufsz);
                if (ret)
-                       break;
+                       goto out_free_digest;
 
                /*
                 * Assume rest of the buffer is filled with zero and
@@ -777,32 +777,26 @@ static int kexec_calculate_store_digests(struct kimage 
*image)
                                bytes = zero_buf_sz;
                        ret = crypto_shash_update(desc, zero_buf, bytes);
                        if (ret)
-                               break;
+                               goto out_free_digest;
                        nullsz -= bytes;
                }
 
-               if (ret)
-                       break;
-
                sha_regions[j].start = ksegment->mem;
                sha_regions[j].len = ksegment->memsz;
                j++;
        }
 
-       if (!ret) {
-               ret = crypto_shash_final(desc, digest);
-               if (ret)
-                       goto out_free_digest;
-               ret = kexec_purgatory_get_set_symbol(image, 
"purgatory_sha_regions",
-                                                    sha_regions, 
sha_region_sz, 0);
-               if (ret)
-                       goto out_free_digest;
+       ret = crypto_shash_final(desc, digest);
+       if (ret)
+               goto out_free_digest;
 
-               ret = kexec_purgatory_get_set_symbol(image, 
"purgatory_sha256_digest",
-                                                    digest, 
SHA256_DIGEST_SIZE, 0);
-               if (ret)
-                       goto out_free_digest;
-       }
+       ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions",
+                                            sha_regions, sha_region_sz, 0);
+       if (ret)
+               goto out_free_digest;
+
+       ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest",
+                                            digest, SHA256_DIGEST_SIZE, 0);
 
 out_free_digest:
        kfree(digest);