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Subject[PATCH] swiotlb: Correct kernel command line handler
Date
This patch corrects kernel command line handler when io_tlb_nslabs
is set to 0.

A current implementation allocates default size memory (64MB) when
0 is given to io_tlb_nslabs ("swiotlb=0") by kernel command line.
In other words, memory is allocated unintentionally.

Signed-off-by: Jungseok Lee <jays.lee@samsung.com>
Signed-off-by: Sungjinn Chung <sungjinn.chung@samsung.com>
---
lib/swiotlb.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index b604b83..9fe9f71 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -55,6 +55,8 @@

int swiotlb_force;

+static int swiotlb_no_use;
+
/*
* Used to do a quick range check in swiotlb_tbl_unmap_single and
* swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
@@ -102,6 +104,8 @@ setup_io_tlb_npages(char *str)
io_tlb_nslabs = simple_strtoul(str, &str, 0);
/* avoid tail segment of size < IO_TLB_SEGSIZE */
io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+ if (!io_tlb_nslabs)
+ swiotlb_no_use = 1;
}
if (*str == ',')
++str;
@@ -212,7 +216,7 @@ swiotlb_init(int verbose)
unsigned char *vstart;
unsigned long bytes;

- if (!io_tlb_nslabs) {
+ if (!swiotlb_no_use && !io_tlb_nslabs) {
io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
}
@@ -244,7 +248,7 @@ swiotlb_late_init_with_default_size(size_t default_size)
unsigned int order;
int rc = 0;

- if (!io_tlb_nslabs) {
+ if (!swiotlb_no_use && !io_tlb_nslabs) {
io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
}
--
1.7.10.4



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