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Date:   Wed, 31 Aug 2022 00:38:18 -0600
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Subject: [PATCH v2] Revert "swiotlb: panic if nslabs is too small"
From:   Yu Zhao <yuzhao@google.com>
To:     Christoph Hellwig <hch@infradead.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Dongli Zhang <dongli.zhang@oracle.com>
Cc:     iommu@lists.linux.dev, linux-mips@vger.kernel.org,
        linux-kernel@vger.kernel.org, Yu Zhao <yuzhao@google.com>,
        kernel test robot <lkp@intel.com>,
        Dan Carpenter <dan.carpenter@oracle.com>
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Precedence: bulk

This reverts commit 0bf28fc40d89b1a3e00d1b79473bad4e9ca20ad1.

Reasons:
  1. new panic()s shouldn't be added [1].
  2. It does no "cleanup" but breaks MIPS [2].

v2: properly solved the conflict [3] with
commit 20347fca71a38 ("swiotlb: split up the global swiotlb lock")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

[1] https://lore.kernel.org/r/CAHk-=wit-DmhMfQErY29JSPjFgebx_Ld+pnerc4J2Ag990WwAA@mail.gmail.com/
[2] https://lore.kernel.org/r/20220820012031.1285979-1-yuzhao@google.com/
[3] https://lore.kernel.org/r/202208310701.LKr1WDCh-lkp@intel.com/

Fixes: 0bf28fc40d89b ("swiotlb: panic if nslabs is too small")
Signed-off-by: Yu Zhao <yuzhao@google.com>
---
 kernel/dma/swiotlb.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index c5a9190b218f..dd8863987e0c 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -326,9 +326,6 @@ void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags,
 		swiotlb_adjust_nareas(num_possible_cpus());
 
 	nslabs = default_nslabs;
-	if (nslabs < IO_TLB_MIN_SLABS)
-		panic("%s: nslabs = %lu too small\n", __func__, nslabs);
-
 	/*
 	 * By default allocate the bounce buffer memory from low memory, but
 	 * allow to pick a location everywhere for hypervisors with guest
@@ -341,8 +338,7 @@ void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags,
 	else
 		tlb = memblock_alloc_low(bytes, PAGE_SIZE);
 	if (!tlb) {
-		pr_warn("%s: Failed to allocate %zu bytes tlb structure\n",
-			__func__, bytes);
+		pr_warn("%s: failed to allocate tlb structure\n", __func__);
 		return;
 	}
 

base-commit: dcf8e5633e2e69ad60b730ab5905608b756a032f
-- 
2.37.2.672.g94769d06f0-goog