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From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Kees Cook <keescook@chromium.org>,
	Segher Boessenkool <segher@kernel.crashing.org>,
	Kernel Hardening <kernel-hardening@lists.openwall.com>,
	Andrew Morton <akpm@linuxfoundation.org>,
	Boris Brezillon <boris.brezillon@free-electrons.com>,
	Richard Weinberger <richard@nod.at>,
	David Woodhouse <dwmw2@infradead.org>,
	Alasdair Kergon <agk@redhat.com>,
	Mike Snitzer <snitzer@redhat.com>,
	Anton Vorontsov <anton@enomsg.org>,
	Colin Cross <ccross@android.com>, Tony Luck <tony.luck@intel.com>,
	Boris Brezillon <boris.brezillon@bootlin.com>
Subject: [patch V3 09/10] mtd: rawnand: diskonchip: Allocate rs control per instance
Date: Sun, 22 Apr 2018 18:23:54 +0200	[thread overview]
Message-ID: <20180422162513.093459051@linutronix.de> (raw)
In-Reply-To: <20180422162345.004292133@linutronix.de>

[-- Attachment #1: mtd-diskonchip--Allocate_rs_control_per_instance.patch --]
[-- Type: text/plain, Size: 5232 bytes --]

From: Thomas Gleixner <tglx@linutronix.de>

The reed solomon library is moving the on stack decoder buffers into the rs
control structure. That would break the DoC driver because multiple
instances share the same control structure and can operate in parallel. At
least in theory....

Instantiate a rs control instance per DoC device to avoid that. The per
instance buffer is fine as the operation on a single DoC instance is
serialized by the MTD/NAND core.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Boris Brezillon <boris.brezillon@bootlin.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Andrew Morton <akpm@linuxfoundation.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Alasdair Kergon <agk@redhat.com>

---
 drivers/mtd/nand/raw/diskonchip.c |   60 +++++++++++++++++---------------------
 1 file changed, 27 insertions(+), 33 deletions(-)

--- a/drivers/mtd/nand/raw/diskonchip.c
+++ b/drivers/mtd/nand/raw/diskonchip.c
@@ -66,6 +66,7 @@ struct doc_priv {
 	int curchip;
 	int mh0_page;
 	int mh1_page;
+	struct rs_control *rs_decoder;
 	struct mtd_info *nextdoc;
 
 	/* Handle the last stage of initialization (BBT scan, partitioning) */
@@ -123,9 +124,6 @@ MODULE_PARM_DESC(doc_config_location, "P
 /* Number of symbols */
 #define NN 1023
 
-/* the Reed Solomon control structure */
-static struct rs_control *rs_decoder;
-
 /*
  * The HW decoder in the DoC ASIC's provides us a error syndrome,
  * which we must convert to a standard syndrome usable by the generic
@@ -931,7 +929,7 @@ static int doc200x_correct_data(struct m
 				calc_ecc[i] = ReadDOC_(docptr, DoC_ECCSyndrome0 + i);
 		}
 
-		ret = doc_ecc_decode(rs_decoder, dat, calc_ecc);
+		ret = doc_ecc_decode(doc->rs_decoder, dat, calc_ecc);
 		if (ret > 0)
 			pr_err("doc200x_correct_data corrected %d errors\n",
 			       ret);
@@ -1422,10 +1420,10 @@ static inline int __init doc2001plus_ini
 
 static int __init doc_probe(unsigned long physadr)
 {
+	struct nand_chip *nand = NULL;
+	struct doc_priv *doc = NULL;
 	unsigned char ChipID;
 	struct mtd_info *mtd;
-	struct nand_chip *nand;
-	struct doc_priv *doc;
 	void __iomem *virtadr;
 	unsigned char save_control;
 	unsigned char tmp, tmpb, tmpc;
@@ -1562,8 +1560,25 @@ static int __init doc_probe(unsigned lon
 		goto fail;
 	}
 
+
+	/*
+	 * Allocate a RS codec instance
+	 *
+	 * Symbolsize is 10 (bits)
+	 * Primitve polynomial is x^10+x^3+1
+	 * First consecutive root is 510
+	 * Primitve element to generate roots = 1
+	 * Generator polinomial degree = 4
+	 */
+	doc = (struct doc_priv *) (nand + 1);
+	doc->rs_decoder = init_rs(10, 0x409, FCR, 1, NROOTS);
+	if (!doc->rs_decoder) {
+		pr_err("DiskOnChip: Could not create a RS codec\n");
+		ret = -ENOMEM;
+		goto fail;
+	}
+
 	mtd			= nand_to_mtd(nand);
-	doc			= (struct doc_priv *) (nand + 1);
 	nand->bbt_td		= (struct nand_bbt_descr *) (doc + 1);
 	nand->bbt_md		= nand->bbt_td + 1;
 
@@ -1613,7 +1628,6 @@ static int __init doc_probe(unsigned lon
 		   haven't yet added it.  This is handled without incident by
 		   mtd_device_unregister, as far as I can tell. */
 		nand_release(mtd);
-		kfree(nand);
 		goto fail;
 	}
 
@@ -1626,6 +1640,9 @@ static int __init doc_probe(unsigned lon
 	   actually a DiskOnChip.  */
 	WriteDOC(save_control, virtadr, DOCControl);
  fail:
+	if (doc)
+		free_rs(doc->rs_decoder);
+	kfree(nand);
 	iounmap(virtadr);
 
 error_ioremap:
@@ -1648,6 +1665,7 @@ static void release_nanddoc(void)
 		nand_release(mtd);
 		iounmap(doc->virtadr);
 		release_mem_region(doc->physadr, DOC_IOREMAP_LEN);
+		free_rs(doc->rs_decoder);
 		kfree(nand);
 	}
 }
@@ -1656,27 +1674,12 @@ static int __init init_nanddoc(void)
 {
 	int i, ret = 0;
 
-	/* We could create the decoder on demand, if memory is a concern.
-	 * This way we have it handy, if an error happens
-	 *
-	 * Symbolsize is 10 (bits)
-	 * Primitve polynomial is x^10+x^3+1
-	 * first consecutive root is 510
-	 * primitve element to generate roots = 1
-	 * generator polinomial degree = 4
-	 */
-	rs_decoder = init_rs(10, 0x409, FCR, 1, NROOTS);
-	if (!rs_decoder) {
-		pr_err("DiskOnChip: Could not create a RS decoder\n");
-		return -ENOMEM;
-	}
-
 	if (doc_config_location) {
 		pr_info("Using configured DiskOnChip probe address 0x%lx\n",
 			doc_config_location);
 		ret = doc_probe(doc_config_location);
 		if (ret < 0)
-			goto outerr;
+			return ret;
 	} else {
 		for (i = 0; (doc_locations[i] != 0xffffffff); i++) {
 			doc_probe(doc_locations[i]);
@@ -1687,11 +1690,7 @@ static int __init init_nanddoc(void)
 	if (!doclist) {
 		pr_info("No valid DiskOnChip devices found\n");
 		ret = -ENODEV;
-		goto outerr;
 	}
-	return 0;
- outerr:
-	free_rs(rs_decoder);
 	return ret;
 }
 
@@ -1699,11 +1698,6 @@ static void __exit cleanup_nanddoc(void)
 {
 	/* Cleanup the nand/DoC resources */
 	release_nanddoc();
-
-	/* Free the reed solomon resources */
-	if (rs_decoder) {
-		free_rs(rs_decoder);
-	}
 }
 
 module_init(init_nanddoc);

  parent reply	other threads:[~2018-04-22 16:23 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-22 16:23 [patch V3 00/10] rslib: Cleanup and VLA removal Thomas Gleixner
2018-04-22 16:23 ` [patch V3 01/10] rslib: Add GFP aware init function Thomas Gleixner
2018-04-25  1:16   ` Stephen Rothwell
2018-04-25  2:45     ` Kees Cook
2018-04-25  8:59       ` Thomas Gleixner
2018-04-22 16:23 ` [patch V3 02/10] dm/verity_fec: Use GFP aware reed solomon init Thomas Gleixner
2018-04-22 16:23 ` [patch V3 03/10] rslib: Cleanup whitespace damage Thomas Gleixner
2018-04-22 16:23 ` [patch V3 04/10] rslib: Cleanup top level comments Thomas Gleixner
2018-04-22 16:23 ` [patch V3 05/10] rslib: Add SPDX identifiers Thomas Gleixner
2018-04-22 16:23 ` [patch V3 06/10] rslib: Remove GPL boilerplate Thomas Gleixner
2018-04-22 16:23 ` [patch V3 07/10] rslib: Simplify error path Thomas Gleixner
2018-04-22 16:23 ` [patch V3 08/10] rslib: Split rs control struct Thomas Gleixner
2018-04-22 16:23 ` Thomas Gleixner [this message]
2018-04-22 16:23 ` [patch V3 10/10] rslib: Allocate decoder buffers to avoid VLAs Thomas Gleixner
2018-04-24 16:42 ` [patch V3 00/10] rslib: Cleanup and VLA removal Kees Cook

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