Kernel News: LWN Articles (Freed From Paywall), Coreboot, and Bootlin
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Crash recovery for user-space block drivers [LWN.net]
A new user-space block driver mechanism entered the kernel during the 6.0 merge window. This subsystem, called "ublk", uses io_uring to communicate with user-space drivers, resulting in some impressive performance numbers. Ublk has a lot of interesting potential, but the current use cases for it are not entirely clear. The recently posted crash-recovery mechanism for ublk makes it clear, though, that those use cases do exist.
If an in-kernel block driver crashes, it is likely to bring down the entire kernel with it. Putting those drivers into user space can, theoretically, result in a more robust system, since the kernel can now survive a driver crash. With ublk as found in the 6.0 kernel, though, a driver crash will result in the associated devices disappearing and all outstanding I/O requests failing.
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Toward a better definition for i_version [LWN.net]
Filesystems maintain a lot of metadata about the files they hold; most of this metadata is for consumption by user space. Some metadata, though, stays buried within the filesystem and is not visible outside of the kernel. One such piece of metadata is the file version count, known as i_version. Current efforts to change how i_version is managed — and to make it visible to user space — have engendered a debate on what i_version actually means and what its behavior should be.
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Ushering out strlcpy() [LWN.net]
With all of the complex problems that must be solved in the kernel, one might think that copying a string would draw little attention. Even with the hazards that C strings present, simply moving some bytes should not be all that hard. But string-copy functions have been a frequent subject of debate over the years, with different variants being in fashion at times. Now it seems that the BSD-derived strlcpy() function may finally be on its way out of the kernel.
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Debian to vote on its firmware path
Dealing with the non-free firmware that is increasingly needed to install Debian has been a hot topic for the distribution over the past few months. The problem goes back further still, of course, but Steve McIntyre re-raised the issue in April, which resulted in a predictable lengthy discussion thread on the debian-devel mailing list. Now McIntyre has proposed a general resolution (GR) with the intent of resolving how to give users a way to install the distribution on their hardware while trying to avoid trampling on the "100% free" guarantee in the Debian Social Contract. Finding the right balance is going to be tricky as is shown by the multiple GR options that have been proposed in the discussion.
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[GSoC] Optimize Erase Function Selection, wrap-up - coreboot
GSoC 2022 coding period is about to come to an end this week. It has been an enriching 12 weeks of reading old code, designing algorithms and structures, coding, testing, and hanging out over IRC! I’d like to take this opportunity to present my work and details on how it has impacted Flashrom. 🙂
You can find the complete list of commits I made during GSoC with this gerrit query. Some of the patches aren’t currently merged and are under review. In any case, you are most welcome to join the review (which will likely be very helpful for me).
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Bootlin at Linux Plumbers conference 2022 - Bootlin's blog
Next week, almost the entire Bootlin team will be at the Embedded Linux Conference Europe in Dublin, see our previous blog post on this topic. We will give four talks at this event, on a variety of Linux kernel and embedded Linux topics.
During the same week, also in Dublin albeit in a different location, will take place the Linux Plumbers conference. Bootlin engineer Miquèl Raynal will give a talk at Linux Plumbers, as part of the IoTs a 4-Letter Word micro-conference. Miquèl’s talk will discuss Linux IEEE 802.15.4 MLME improvements, as Miquèl has been working for several months on bringing improvements to the 802.15.4 stack in the Linux kernel.