From: Dongli Zhang <dongli.zhang@oracle.com>
Date: Mon, 1 Apr 2019 06:30:05 +0000 (+0800)
Subject: swiotlb: checking whether swiotlb buffer is full with io_tlb_used
X-Git-Tag: v4.1.12-124.31.3~208
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=ec98a38a45459a0f779685588b3f3df23969ba2e;p=users%2Fjedix%2Flinux-maple.git

swiotlb: checking whether swiotlb buffer is full with io_tlb_used

This patch uses io_tlb_used to help check whether swiotlb buffer is full.
io_tlb_used is no longer used for only debugfs. It is also used to help
optimize swiotlb_tbl_map_single().

Suggested-by: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Orabug: 29582587
(cherry picked from commit 60513ed06a41049768a6875229b025b6e726e148)

Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Brian Maly <brian.maly@oracle.com>
---

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index f41f1be70367..c9d2b32c70b5 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -476,6 +476,10 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
 	 * request and allocate a buffer from that IO TLB pool.
 	 */
 	spin_lock_irqsave(&io_tlb_lock, flags);
+
+	if (unlikely(nslots > io_tlb_nslabs - io_tlb_used))
+		goto not_found;
+
 	index = ALIGN(io_tlb_index, stride);
 	if (index >= io_tlb_nslabs)
 		index = 0;