mtd: nand: Remove BUG() abuse in nand_scan_tail

There's no reason to BUG() when parameters are being
validated. Drivers can get things wrong, and it's much nicer
to just throw a noisy warn and fail gracefully, than calling
BUG() and throwing the whole system down the drain.

Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 728543b97dd814c5ba6a7397ab654701681b7aa6..0f0c5b190316d63e0d8e75b152b2242b95aa3442 100644 (file)
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -4107,10 +4107,12 @@ int nand_scan_tail(struct mtd_info *mtd)
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct nand_ecc_ctrl *ecc = &chip->ecc;
        struct nand_buffers *nbuf;
+       int ret;
 
        /* New bad blocks should be marked in OOB, flash-based BBT, or both */
-       BUG_ON((chip->bbt_options & NAND_BBT_NO_OOB_BBM) &&
-                       !(chip->bbt_options & NAND_BBT_USE_FLASH));
+       if (WARN_ON((chip->bbt_options & NAND_BBT_NO_OOB_BBM) &&
+                  !(chip->bbt_options & NAND_BBT_USE_FLASH)))
+               return -EINVAL;
 
        if (!(chip->options & NAND_OWN_BUFFERS)) {
                nbuf = kzalloc(sizeof(*nbuf) + mtd->writesize
@@ -4148,9 +4150,10 @@ int nand_scan_tail(struct mtd_info *mtd)
                        ecc->layout = &nand_oob_128;
                        break;
                default:
-                       pr_warn("No oob scheme defined for oobsize %d\n",
-                                  mtd->oobsize);
-                       BUG();
+                       WARN(1, "No oob scheme defined for oobsize %d\n",
+                               mtd->oobsize);
+                       ret = -EINVAL;
+                       goto err_free;
                }
        }
 
@@ -4166,8 +4169,9 @@ int nand_scan_tail(struct mtd_info *mtd)
        case NAND_ECC_HW_OOB_FIRST:
                /* Similar to NAND_ECC_HW, but a separate read_page handle */
                if (!ecc->calculate || !ecc->correct || !ecc->hwctl) {
-                       pr_warn("No ECC functions supplied; hardware ECC not possible\n");
-                       BUG();
+                       WARN(1, "No ECC functions supplied; hardware ECC not possible\n");
+                       ret = -EINVAL;
+                       goto err_free;
                }
                if (!ecc->read_page)
                        ecc->read_page = nand_read_page_hwecc_oob_first;
@@ -4197,8 +4201,9 @@ int nand_scan_tail(struct mtd_info *mtd)
                     ecc->read_page == nand_read_page_hwecc ||
                     !ecc->write_page ||
                     ecc->write_page == nand_write_page_hwecc)) {
-                       pr_warn("No ECC functions supplied; hardware ECC not possible\n");
-                       BUG();
+                       WARN(1, "No ECC functions supplied; hardware ECC not possible\n");
+                       ret = -EINVAL;
+                       goto err_free;
                }
                /* Use standard syndrome read/write page function? */
                if (!ecc->read_page)
@@ -4216,8 +4221,9 @@ int nand_scan_tail(struct mtd_info *mtd)
 
                if (mtd->writesize >= ecc->size) {
                        if (!ecc->strength) {
-                               pr_warn("Driver must set ecc.strength when using hardware ECC\n");
-                               BUG();
+                               WARN(1, "Driver must set ecc.strength when using hardware ECC\n");
+                               ret = -EINVAL;
+                               goto err_free;
                        }
                        break;
                }
@@ -4243,8 +4249,9 @@ int nand_scan_tail(struct mtd_info *mtd)
 
        case NAND_ECC_SOFT_BCH:
                if (!mtd_nand_has_bch()) {
-                       pr_warn("CONFIG_MTD_NAND_ECC_BCH not enabled\n");
-                       BUG();
+                       WARN(1, "CONFIG_MTD_NAND_ECC_BCH not enabled\n");
+                       ret = -EINVAL;
+                       goto err_free;
                }
                ecc->calculate = nand_bch_calculate_ecc;
                ecc->correct = nand_bch_correct_data;
@@ -4269,8 +4276,9 @@ int nand_scan_tail(struct mtd_info *mtd)
                ecc->bytes = 0;
                ecc->priv = nand_bch_init(mtd);
                if (!ecc->priv) {
-                       pr_warn("BCH ECC initialization failed!\n");
-                       BUG();
+                       WARN(1, "BCH ECC initialization failed!\n");
+                       ret = -EINVAL;
+                       goto err_free;
                }
                break;
 
@@ -4288,8 +4296,9 @@ int nand_scan_tail(struct mtd_info *mtd)
                break;
 
        default:
-               pr_warn("Invalid NAND_ECC_MODE %d\n", ecc->mode);
-               BUG();
+               WARN(1, "Invalid NAND_ECC_MODE %d\n", ecc->mode);
+               ret = -EINVAL;
+               goto err_free;
        }
 
        /* For many systems, the standard OOB write also works for raw */
@@ -4319,8 +4328,9 @@ int nand_scan_tail(struct mtd_info *mtd)
         */
        ecc->steps = mtd->writesize / ecc->size;
        if (ecc->steps * ecc->size != mtd->writesize) {
-               pr_warn("Invalid ECC parameters\n");
-               BUG();
+               WARN(1, "Invalid ECC parameters\n");
+               ret = -EINVAL;
+               goto err_free;
        }
        ecc->total = ecc->steps * ecc->bytes;
 
@@ -4398,6 +4408,10 @@ int nand_scan_tail(struct mtd_info *mtd)
 
        /* Build bad block table */
        return chip->scan_bbt(mtd);
+err_free:
+       if (!(chip->options & NAND_OWN_BUFFERS))
+               kfree(chip->buffers);
+       return ret;
 }
 EXPORT_SYMBOL(nand_scan_tail);