/* * Load Analog Devices SigmaStudio firmware files * * Copyright 2009-2011 Analog Devices Inc. * * Licensed under the GPL-2 or later. */ #include #include #include #include #include #include "sigmadsp.h" static int sigmadsp_write_i2c(void *control_data, unsigned int addr, const uint8_t data[], size_t len) { uint8_t *buf; int ret; buf = kzalloc(2 + len, GFP_KERNEL | GFP_DMA); if (!buf) return -ENOMEM; put_unaligned_be16(addr, buf); memcpy(buf + 2, data, len); ret = i2c_master_send(control_data, buf, len + 2); kfree(buf); if (ret < 0) return ret; return 0; } static int sigmadsp_read_i2c(void *control_data, unsigned int addr, uint8_t data[], size_t len) { struct i2c_client *client = control_data; struct i2c_msg msgs[2]; uint8_t buf[2]; int ret; put_unaligned_be16(addr, buf); msgs[0].addr = client->addr; msgs[0].len = sizeof(buf); msgs[0].buf = buf; msgs[0].flags = 0; msgs[1].addr = client->addr; msgs[1].len = len; msgs[1].buf = data; msgs[1].flags = I2C_M_RD; ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); if (ret < 0) return ret; else if (ret != ARRAY_SIZE(msgs)) return -EIO; return 0; } /** * devm_sigmadsp_init_i2c() - Initialize SigmaDSP instance * @client: The parent I2C device * @ops: The sigmadsp_ops to use for this instance * @firmware_name: Name of the firmware file to load * * Allocates a SigmaDSP instance and loads the specified firmware file. * * Returns a pointer to a struct sigmadsp on success, or a PTR_ERR() on error. */ struct sigmadsp *devm_sigmadsp_init_i2c(struct i2c_client *client, const struct sigmadsp_ops *ops, const char *firmware_name) { struct sigmadsp *sigmadsp; sigmadsp = devm_sigmadsp_init(&client->dev, ops, firmware_name); if (IS_ERR(sigmadsp)) return sigmadsp; sigmadsp->control_data = client; sigmadsp->write = sigmadsp_write_i2c; sigmadsp->read = sigmadsp_read_i2c; return sigmadsp; } EXPORT_SYMBOL_GPL(devm_sigmadsp_init_i2c); MODULE_AUTHOR("Lars-Peter Clausen "); MODULE_DESCRIPTION("SigmaDSP I2C firmware loader"); MODULE_LICENSE("GPL"); me='qt'>
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authorEric W. Biederman <ebiederm@xmission.com>2017-01-03 14:18:43 +1300
committerEric W. Biederman <ebiederm@xmission.com>2017-01-10 13:34:43 +1300
commit3895dbf8985f656675b5bde610723a29cbce3fa7 (patch)
tree91d4517f09918fd573998eb40b8f35f08ed1c470
parent0c744ea4f77d72b3dcebb7a8f2684633ec79be88 (diff)
mnt: Protect the mountpoint hashtable with mount_lock
Protecting the mountpoint hashtable with namespace_sem was sufficient until a call to umount_mnt was added to mntput_no_expire. At which point it became possible for multiple calls of put_mountpoint on the same hash chain to happen on the same time. Kristen Johansen <kjlx@templeofstupid.com> reported: > This can cause a panic when simultaneous callers of put_mountpoint > attempt to free the same mountpoint. This occurs because some callers > hold the mount_hash_lock, while others hold the namespace lock. Some > even hold both. > > In this submitter's case, the panic manifested itself as a GP fault in > put_mountpoint() when it called hlist_del() and attempted to dereference > a m_hash.pprev that had been poisioned by another thread. Al Viro observed that the simple fix is to switch from using the namespace_sem to the mount_lock to protect the mountpoint hash table. I have taken Al's suggested patch moved put_mountpoint in pivot_root (instead of taking mount_lock an additional time), and have replaced new_mountpoint with get_mountpoint a function that does the hash table lookup and addition under the mount_lock. The introduction of get_mounptoint ensures that only the mount_lock is needed to manipulate the mountpoint hashtable. d_set_mounted is modified to only set DCACHE_MOUNTED if it is not already set. This allows get_mountpoint to use the setting of DCACHE_MOUNTED to ensure adding a struct mountpoint for a dentry happens exactly once. Cc: stable@vger.kernel.org Fixes: ce07d891a089 ("mnt: Honor MNT_LOCKED when detaching mounts") Reported-by: Krister Johansen <kjlx@templeofstupid.com> Suggested-by: Al Viro <viro@ZenIV.linux.org.uk> Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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