[RFC PATCH] disk: Don't loop over MAX_SEARCH_PARTITIONS in part_create_block_devices()

Stefan Roese sr at denx.de
Tue Jan 10 09:00:38 CET 2023

I've noticed that the first ext4 file loading from a MMC partition for
ZynqMP takes quite some time (~ 1 second). Debugging showed, that the
MMC driver reads the partition info 128 time (MAX_SEARCH_PARTITIONS)
resulting in this boot delay. To fix this, let's just end creating the
block drives in part_create_block_devices() when no more valid partition
is found. This reduces the first file reading from ~0.9s to ~0.3s.

Signed-off-by: Stefan Roese <sr at denx.de>
Cc: Simon Glass <sjg at chromium.org>
Cc: AKASHI Takahiro <takahiro.akashi at linaro.org>
Cc: Heinrich Schuchardt <xypron.glpk at gmx.de>
Reasoning for RFC:
I did not dig into the current disk / partition stuff too deeply, so I'm
not 100% sure that this patch does not break anything.
 disk/disk-uclass.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/disk/disk-uclass.c b/disk/disk-uclass.c
index d32747e2242d..2999f7285b5a 100644
--- a/disk/disk-uclass.c
+++ b/disk/disk-uclass.c
@@ -36,7 +36,7 @@ int part_create_block_devices(struct udevice *blk_dev)
 	/* Add devices for each partition */
 	for (count = 0, part = 1; part <= MAX_SEARCH_PARTITIONS; part++) {
 		if (part_get_info(desc, part, &info))
-			continue;
+			break;
 		snprintf(devname, sizeof(devname), "%s:%d", blk_dev->name,

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